7 earth materials

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Chapter 7

Earth materials

Earth materials is a general term that includesminerals,rocks,soilandwater. These are the

naturally occurring materials found onEarththat constitute theraw materialsupon which our global

society exists. Earth materials are vital resources that provide the basic components for

life,agricultureandindustry.

Earth materials can also includemetalsandprecious rocks

Minerals close-up

A pile of mineralsThis image shows some of themost common minerals you'll findin rocks. This pilecontainsplagioclasefeldspar,potassiumfeldspar,quartz,muscovitemica,biotitemica,amphibole,olivine,andcalcite. Can you identify any

of them? Click on any mineral for aclose up view.

Quartz

Quartz is one of the most common mineralsin the Earth's crust. It is made up of silicondioxide (SiO2), otherwise known assilica.White sand is primarily made from quartz.Clickhereto find out more.
http://en.wikipedia.org/wiki/Mineralhttp://en.wikipedia.org/wiki/Mineralhttp://en.wikipedia.org/wiki/Mineralhttp://en.wikipedia.org/wiki/Rock_(geology)http://en.wikipedia.org/wiki/Rock_(geology)http://en.wikipedia.org/wiki/Rock_(geology)http://en.wikipedia.org/wiki/Soilhttp://en.wikipedia.org/wiki/Soilhttp://en.wikipedia.org/wiki/Soilhttp://en.wikipedia.org/wiki/Waterhttp://en.wikipedia.org/wiki/Waterhttp://en.wikipedia.org/wiki/Waterhttp://en.wikipedia.org/wiki/Earthhttp://en.wikipedia.org/wiki/Earthhttp://en.wikipedia.org/wiki/Earthhttp://en.wikipedia.org/wiki/Raw_materialhttp://en.wikipedia.org/wiki/Raw_materialhttp://en.wikipedia.org/wiki/Raw_materialhttp://en.wikipedia.org/wiki/Agriculturehttp://en.wikipedia.org/wiki/Agriculturehttp://en.wikipedia.org/wiki/Agriculturehttp://en.wikipedia.org/wiki/Industryhttp://en.wikipedia.org/wiki/Industryhttp://en.wikipedia.org/wiki/Industryhttp://en.wikipedia.org/wiki/Metalhttp://en.wikipedia.org/wiki/Metalhttp://en.wikipedia.org/wiki/Metalhttp://en.wikipedia.org/wiki/Precious_stonehttp://en.wikipedia.org/wiki/Precious_stonehttp://en.wikipedia.org/wiki/Precious_stonehttp://geomaps.wr.usgs.gov/parks/rxmin/mineral.html#plagioclasehttp://geomaps.wr.usgs.gov/parks/rxmin/mineral.html#plagioclasehttp://geomaps.wr.usgs.gov/parks/rxmin/mineral.html#plagioclasehttp://geomaps.wr.usgs.gov/parks/rxmin/mineral.html#ksparhttp://geomaps.wr.usgs.gov/parks/rxmin/mineral.html#ksparhttp://geomaps.wr.usgs.gov/parks/rxmin/mineral.html#ksparhttp://geomaps.wr.usgs.gov/parks/rxmin/mineral.html#quartzhttp://geomaps.wr.usgs.gov/parks/rxmin/mineral.html#quartzhttp://geomaps.wr.usgs.gov/parks/rxmin/mineral.html#quartzhttp://geomaps.wr.usgs.gov/parks/rxmin/mineral.html#micahttp://geomaps.wr.usgs.gov/parks/rxmin/mineral.html#micahttp://geomaps.wr.usgs.gov/parks/rxmin/mineral.html#micahttp://geomaps.wr.usgs.gov/parks/rxmin/mineral.html#micahttp://geomaps.wr.usgs.gov/parks/rxmin/mineral.html#biotitehttp://geomaps.wr.usgs.gov/parks/rxmin/mineral.html#biotitehttp://geomaps.wr.usgs.gov/parks/rxmin/mineral.html#biotitehttp://geomaps.wr.usgs.gov/parks/rxmin/mineral.html#amphibolehttp://geomaps.wr.usgs.gov/parks/rxmin/mineral.html#amphibolehttp://geomaps.wr.usgs.gov/parks/rxmin/mineral.html#amphibolehttp://geomaps.wr.usgs.gov/parks/rxmin/mineral.html#olivinehttp://geomaps.wr.usgs.gov/parks/rxmin/mineral.html#olivinehttp://geomaps.wr.usgs.gov/parks/rxmin/mineral.html#olivinehttp://geomaps.wr.usgs.gov/parks/rxmin/mineral.html#calcitehttp://geomaps.wr.usgs.gov/parks/rxmin/mineral.html#calcitehttp://geomaps.wr.usgs.gov/parks/rxmin/mineral.html#calcitehttp://geomaps.wr.usgs.gov/parks/misc/glossarys.html#silicahttp://geomaps.wr.usgs.gov/parks/misc/glossarys.html#silicahttp://geomaps.wr.usgs.gov/parks/misc/glossarys.html#silicahttp://geomaps.wr.usgs.gov/parks/coast/sand/sand.htmlhttp://geomaps.wr.usgs.gov/parks/coast/sand/sand.htmlhttp://geomaps.wr.usgs.gov/parks/coast/sand/sand.htmlhttp://geomaps.wr.usgs.gov/parks/coast/sand/sand.htmlhttp://geomaps.wr.usgs.gov/parks/misc/glossarys.html#silicahttp://geomaps.wr.usgs.gov/parks/rxmin/mineral.html#calcitehttp://geomaps.wr.usgs.gov/parks/rxmin/mineral.html#olivinehttp://geomaps.wr.usgs.gov/parks/rxmin/mineral.html#amphibolehttp://geomaps.wr.usgs.gov/parks/rxmin/mineral.html#biotitehttp://geomaps.wr.usgs.gov/parks/rxmin/mineral.html#biotitehttp://geomaps.wr.usgs.gov/parks/rxmin/mineral.html#micahttp://geomaps.wr.usgs.gov/parks/rxmin/mineral.html#micahttp://geomaps.wr.usgs.gov/parks/rxmin/mineral.html#quartzhttp://geomaps.wr.usgs.gov/parks/rxmin/mineral.html#ksparhttp://geomaps.wr.usgs.gov/parks/rxmin/mineral.html#ksparhttp://geomaps.wr.usgs.gov/parks/rxmin/mineral.html#plagioclasehttp://geomaps.wr.usgs.gov/parks/rxmin/mineral.html#plagioclasehttp://en.wikipedia.org/wiki/Precious_stonehttp://en.wikipedia.org/wiki/Metalhttp://en.wikipedia.org/wiki/Industryhttp://en.wikipedia.org/wiki/Agriculturehttp://en.wikipedia.org/wiki/Raw_materialhttp://en.wikipedia.org/wiki/Earthhttp://en.wikipedia.org/wiki/Waterhttp://en.wikipedia.org/wiki/Soilhttp://en.wikipedia.org/wiki/Rock_(geology)http://en.wikipedia.org/wiki/Mineral


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Plagioclase feldspar

Plagioclase is a member ofthe feldspar mineral family. Plagioclasefeldspars are yet anothersilicatethat

contains considerable sodium or calcium.Feldspar crystals are stubby prisms, generallywhite to gray and a glassyluster. This varietyof plagioclase, called albite, is rich in sodium.

Potassium feldspar

Potassium feldspar is another member ofthe feldsparmineral family. Likeplagioclase feldspar, potassium feldsparsaresilicateminerals that contain aconsiderable amount of -you guessed it-potassium. Feldspar crystals are stubbyprisms, often pink to white. Somepotassium feldspars, such as the oneshown to the left have a streakyappearance (see closeup) called perthitic

texture.

Mica

Micas are another group ofsilicatemineralscomposed of varying amounts of potassium,magnesium, iron as well as aluminum, siliconand water.

Biotite

All micas form flat, book-like crystalsthat peal apart into individual sheetsoncleavageplanes. Crystals cleaveinto smooth flakes. Biotiteis dark,black or brown mica; muscovite,shown here, is light-colored or clearmica. Mica is so soft that you can

scratch it with a fingernail.
http://geomaps.wr.usgs.gov/parks/misc/glossarys.html#silicahttp://geomaps.wr.usgs.gov/parks/misc/glossarys.html#silicahttp://geomaps.wr.usgs.gov/parks/misc/glossarys.html#silicahttp://geomaps.wr.usgs.gov/parks/misc/glossaryjkl.html#lusterhttp://geomaps.wr.usgs.gov/parks/misc/glossaryjkl.html#lusterhttp://geomaps.wr.usgs.gov/parks/misc/glossaryjkl.html#lusterhttp://geomaps.wr.usgs.gov/parks/misc/glossarys.html#silicahttp://geomaps.wr.usgs.gov/parks/misc/glossarys.html#silicahttp://geomaps.wr.usgs.gov/parks/misc/glossarys.html#silicahttp://geomaps.wr.usgs.gov/parks/misc/glossarys.html#silicatehttp://geomaps.wr.usgs.gov/parks/misc/glossarys.html#silicatehttp://geomaps.wr.usgs.gov/parks/misc/glossarys.html#silicatehttp://geomaps.wr.usgs.gov/parks/misc/glossaryc.html#cleavagehttp://geomaps.wr.usgs.gov/parks/misc/glossaryc.html#cleavagehttp://geomaps.wr.usgs.gov/parks/misc/glossaryc.html#cleavagehttp://geomaps.wr.usgs.gov/parks/misc/glossaryc.html#cleavagehttp://geomaps.wr.usgs.gov/parks/misc/glossarys.html#silicatehttp://geomaps.wr.usgs.gov/parks/misc/glossarys.html#silicahttp://geomaps.wr.usgs.gov/parks/misc/glossaryjkl.html#lusterhttp://geomaps.wr.usgs.gov/parks/misc/glossarys.html#silica


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Amphibole

The amphiboles are a familyofsilicateminerals that form prism or needle-like crystals. Amphibole minerals generally

contain iron, magnesium, calcium andaluminum in varying amounts along with silicon,oxygen, and water. Hornblende, shown in thisimage, is a common dark green to black variety

of amphibole; it is a component in manyigneousandmetamorphicrocks.

Olivine

Olivine is anothersilicatemineralcontaining iron and magnesium. It is agreen, glassy mineral that forms at high

temperature. It is common inbasaltandinultramaficrocks. Gem-quality olivine iscalled peridote. A rock made up entirely ofolivine is called dunite.

Calcite

Calcite is made of calcium carbonate (CaCO3).Generally white to clear, it is easily scratchedwith knife. Most seashells are made of calcite orrelated minerals. This is the 'lime' oflimestone.

Physical properties of minerals

Classifying minerals can range from simple to very difficult. A mineral can be identified by several

physical properties, some of them being sufficient for full identification without equivocation. In other

cases, minerals can only be classified by more complexoptical, chemical orX-ray diffractionanalysis;

these methods, however, can be costly and time-consuming.

Physical properties commonly used are:[1]

Crystal structure and habit: See the above discussion of crystal structure. A mineral may show

good crystal habit or form, or it may be massive, granular or compact with only microscopically

visible crystals.
http://geomaps.wr.usgs.gov/parks/misc/glossarys.html#silicatehttp://geomaps.wr.usgs.gov/parks/misc/glossarys.html#silicatehttp://geomaps.wr.usgs.gov/parks/misc/glossarys.html#silicatehttp://geomaps.wr.usgs.gov/parks/misc/glossaryi.html#igneoushttp://geomaps.wr.usgs.gov/parks/misc/glossaryi.html#igneoushttp://geomaps.wr.usgs.gov/parks/misc/glossaryi.html#igneoushttp://geomaps.wr.usgs.gov/parks/misc/glossarymn.html#metamorphichttp://geomaps.wr.usgs.gov/parks/misc/glossarymn.html#metamorphichttp://geomaps.wr.usgs.gov/parks/misc/glossarys.html#silicatehttp://geomaps.wr.usgs.gov/parks/misc/glossarys.html#silicatehttp://geomaps.wr.usgs.gov/parks/misc/glossarys.html#silicatehttp://geomaps.wr.usgs.gov/parks/misc/glossaryb.html#basalthttp://geomaps.wr.usgs.gov/parks/misc/glossaryb.html#basalthttp://geomaps.wr.usgs.gov/parks/misc/glossaryb.html#basalthttp://geomaps.wr.usgs.gov/parks/misc/glossaryuv.html#ultramafichttp://geomaps.wr.usgs.gov/parks/misc/glossaryuv.html#ultramafichttp://geomaps.wr.usgs.gov/parks/misc/glossaryuv.html#ultramafichttp://geomaps.wr.usgs.gov/parks/misc/glossaryjkl.html#limestonehttp://geomaps.wr.usgs.gov/parks/misc/glossaryjkl.html#limestonehttp://geomaps.wr.usgs.gov/parks/misc/glossaryjkl.html#limestonehttp://en.wikipedia.org/wiki/Optical_mineralogyhttp://en.wikipedia.org/wiki/Optical_mineralogyhttp://en.wikipedia.org/wiki/Optical_mineralogyhttp://en.wikipedia.org/wiki/X-ray_diffractionhttp://en.wikipedia.org/wiki/X-ray_diffractionhttp://en.wikipedia.org/wiki/X-ray_diffractionhttp://en.wikipedia.org/wiki/Mineral#cite_note-Klein-0http://en.wikipedia.org/wiki/Mineral#cite_note-Klein-0http://en.wikipedia.org/wiki/Mineral#cite_note-Klein-0http://en.wikipedia.org/wiki/Mineral#cite_note-Klein-0http://en.wikipedia.org/wiki/X-ray_diffractionhttp://en.wikipedia.org/wiki/Optical_mineralogyhttp://geomaps.wr.usgs.gov/parks/misc/glossaryjkl.html#limestonehttp://geomaps.wr.usgs.gov/parks/misc/glossaryuv.html#ultramafichttp://geomaps.wr.usgs.gov/parks/misc/glossaryb.html#basalthttp://geomaps.wr.usgs.gov/parks/misc/glossarys.html#silicatehttp://geomaps.wr.usgs.gov/parks/misc/glossarymn.html#metamorphichttp://geomaps.wr.usgs.gov/parks/misc/glossaryi.html#igneoushttp://geomaps.wr.usgs.gov/parks/misc/glossarys.html#silicate


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Talc

Rough diamond.

Hardness: the physical hardness of a mineral is usually measured according to theMohs scale.

This scale is relative and goes from 1 to 10. Minerals with a given Mohs hardness can scratch the

surface of any mineral that has a lower hardness than itself.

Mohs hardness scale:[25]

1. TalcMg3Si4O10(OH)2

2. GypsumCaSO42H2O

3. CalciteCaCO3

4. FluoriteCaF2

5. ApatiteCa5(PO4)3(OH,Cl,F)

6. OrthoclaseKAlSi3O8

7. QuartzSiO2

8. TopazAl2SiO4(OH,F)2

9. CorundumAl2O3

10.DiamondC (pure carbon)

Lusterindicates the way a mineral's surface interacts with light and can range from dull to glassy

(vitreous).

Metallic high reflectivity like metal:galenaandpyrite

Sub-metallic slightly less than metallic reflectivity:magnetite

Non-metallic lusters:

Adamantine brilliant, the luster ofdiamondalsocerussiteandanglesite

Vitreous the luster of a broken glass: quartz

Pearly iridescent and pearl-like: talc andapophyllite

Resinous the luster of resin:sphaleriteandsulfur

Silky a soft light shown by fibrous materials: gypsum andchrysotile

Dull/earthy shown by finely crystallized minerals: the kidney ore variety ofhematite
http://en.wikipedia.org/wiki/Hardness_(materials_science)http://en.wikipedia.org/wiki/Hardness_(materials_science)http://en.wikipedia.org/wiki/Mohs_scale_of_mineral_hardnesshttp://en.wikipedia.org/wiki/Mohs_scale_of_mineral_hardnesshttp://en.wikipedia.org/wiki/Mohs_scale_of_mineral_hardnesshttp://en.wikipedia.org/wiki/Mohs_scale_of_mineral_hardnesshttp://en.wikipedia.org/wiki/Mineral#cite_note-24http://en.wikipedia.org/wiki/Mineral#cite_note-24http://en.wikipedia.org/wiki/Mineral#cite_note-24http://en.wikipedia.org/wiki/Talchttp://en.wikipedia.org/wiki/Talchttp://en.wikipedia.org/wiki/Gypsumhttp://en.wikipedia.org/wiki/Gypsumhttp://en.wikipedia.org/wiki/Calcitehttp://en.wikipedia.org/wiki/Calcitehttp://en.wikipedia.org/wiki/Fluoritehttp://en.wikipedia.org/wiki/Fluoritehttp://en.wikipedia.org/wiki/Apatitehttp://en.wikipedia.org/wiki/Apatitehttp://en.wikipedia.org/wiki/Orthoclasehttp://en.wikipedia.org/wiki/Orthoclasehttp://en.wikipedia.org/wiki/Quartzhttp://en.wikipedia.org/wiki/Quartzhttp://en.wikipedia.org/wiki/Topazhttp://en.wikipedia.org/wiki/Topazhttp://en.wikipedia.org/wiki/Corundumhttp://en.wikipedia.org/wiki/Corundumhttp://en.wikipedia.org/wiki/Diamondhttp://en.wikipedia.org/wiki/Diamondhttp://en.wikipedia.org/wiki/Diamondhttp://en.wikipedia.org/wiki/Luster_(mineralogy)http://en.wikipedia.org/wiki/Luster_(mineralogy)http://en.wikipedia.org/wiki/Galenahttp://en.wikipedia.org/wiki/Galenahttp://en.wikipedia.org/wiki/Galenahttp://en.wikipedia.org/wiki/Pyritehttp://en.wikipedia.org/wiki/Pyritehttp://en.wikipedia.org/wiki/Pyritehttp://en.wikipedia.org/wiki/Magnetitehttp://en.wikipedia.org/wiki/Magnetitehttp://en.wikipedia.org/wiki/Magnetitehttp://en.wikipedia.org/wiki/Diamondhttp://en.wikipedia.org/wiki/Diamondhttp://en.wikipedia.org/wiki/Diamondhttp://en.wikipedia.org/wiki/Cerussitehttp://en.wikipedia.org/wiki/Cerussitehttp://en.wikipedia.org/wiki/Cerussitehttp://en.wikipedia.org/wiki/Anglesitehttp://en.wikipedia.org/wiki/Anglesitehttp://en.wikipedia.org/wiki/Anglesitehttp://en.wikipedia.org/wiki/Apophyllitehttp://en.wikipedia.org/wiki/Apophyllitehttp://en.wikipedia.org/wiki/Apophyllitehttp://en.wikipedia.org/wiki/Sphaleritehttp://en.wikipedia.org/wiki/Sphaleritehttp://en.wikipedia.org/wiki/Sphaleritehttp://en.wikipedia.org/wiki/Sulfurhttp://en.wikipedia.org/wiki/Sulfurhttp://en.wikipedia.org/wiki/Sulfurhttp://en.wikipedia.org/wiki/Chrysotilehttp://en.wikipedia.org/wiki/Chrysotilehttp://en.wikipedia.org/wiki/Chrysotilehttp://en.wikipedia.org/wiki/Hematitehttp://en.wikipedia.org/wiki/Hematitehttp://en.wikipedia.org/wiki/Hematitehttp://en.wikipedia.org/wiki/File:Rough_diamond.jpghttp://en.wikipedia.org/wiki/File:Rough_diamond.jpghttp://en.wikipedia.org/wiki/File:Talc_block.jpghttp://en.wikipedia.org/wiki/File:Talc_block.jpghttp://en.wikipedia.org/wiki/File:Rough_diamond.jpghttp://en.wikipedia.org/wiki/File:Rough_diamond.jpghttp://en.wikipedia.org/wiki/File:Talc_block.jpghttp://en.wikipedia.org/wiki/File:Talc_block.jpghttp://en.wikipedia.org/wiki/File:Rough_diamond.jpghttp://en.wikipedia.org/wiki/File:Rough_diamond.jpghttp://en.wikipedia.org/wiki/File:Talc_block.jpghttp://en.wikipedia.org/wiki/File:Talc_block.jpghttp://en.wikipedia.org/wiki/File:Rough_diamond.jpghttp://en.wikipedia.org/wiki/File:Rough_diamond.jpghttp://en.wikipedia.org/wiki/File:Talc_block.jpghttp://en.wikipedia.org/wiki/File:Talc_block.jpghttp://en.wikipedia.org/wiki/Hematitehttp://en.wikipedia.org/wiki/Chrysotilehttp://en.wikipedia.org/wiki/Sulfurhttp://en.wikipedia.org/wiki/Sphaleritehttp://en.wikipedia.org/wiki/Apophyllitehttp://en.wikipedia.org/wiki/Anglesitehttp://en.wikipedia.org/wiki/Cerussitehttp://en.wikipedia.org/wiki/Diamondhttp://en.wikipedia.org/wiki/Magnetitehttp://en.wikipedia.org/wiki/Pyritehttp://en.wikipedia.org/wiki/Galenahttp://en.wikipedia.org/wiki/Luster_(mineralogy)http://en.wikipedia.org/wiki/Diamondhttp://en.wikipedia.org/wiki/Corundumhttp://en.wikipedia.org/wiki/Topazhttp://en.wikipedia.org/wiki/Quartzhttp://en.wikipedia.org/wiki/Orthoclasehttp://en.wikipedia.org/wiki/Apatitehttp://en.wikipedia.org/wiki/Fluoritehttp://en.wikipedia.org/wiki/Calcitehttp://en.wikipedia.org/wiki/Gypsumhttp://en.wikipedia.org/wiki/Talchttp://en.wikipedia.org/wiki/Mineral#cite_note-24http://en.wikipedia.org/wiki/Mohs_scale_of_mineral_hardnesshttp://en.wikipedia.org/wiki/Mohs_scale_of_mineral_hardnesshttp://en.wikipedia.org/wiki/Hardness_(materials_science)


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Diaphaneitydescribes how well light passes through a mineral; there are three basic degrees of

transparency:

Transparentobjects can be seen through a transparent mineral, such as a clear quartz

crystal

Translucentlight passes through the mineral but no objects can be seen

Opaqueno light passes through the mineral

Many minerals range from transparent to translucent or translucent to opaque. Calcite, for

instance, can be translucent or opaque. Some minerals that are naturally translucent become

opaque with weathering.

Colorindicates the appearance of the mineral in reflected light or transmitted light for

translucent minerals (i.e. what it looks like to the naked eye).

Iridescence the play of colorsdue to surface or internal

interference.Labradoriteexhibits internal iridescence whereas hematite and sphalerite

often show the surface effect.

Streakrefers to the color of the powder a mineral leaves after rubbing it on an unglazed

porcelain streak plate. Note that this is not always the same color as the original mineral.

Cleavagedescribes the way a mineral may split apart along various planes. In thin sections,

cleavage is visible as thin parallel lines across a mineral.

Fracturedescribes how a mineral breaks when broken contrary to its natural cleavage planes.

Chonchoidal fractureis a smooth curved fracture with concentric ridges of the type

shown by glass.

Hackleyis jagged fracture with sharp edges.

Fibrous

Irregular

Specific gravityrelates the mineralmassto the mass of an equal volume of water, namely

thedensityof the material. While most minerals, including all the common rock-forming

minerals, have a specific gravity of 2.53.5, a few are noticeably more or less dense, e.g.

several sulfide minerals have high specific gravity compared to the common rock-forming

minerals.

Other properties:fluorescence(response to ultraviolet

light),magnetism,radioactivity,tenacity(response to mechanical induced changes of shapeor form),piezoelectricityand reactivity to diluteacids.

Chemical properties of minerals

Minerals may be classified according to chemical composition. They are here categorized

byaniongroup. The list below is in approximate order of their abundance in the Earth'scrust. The

list follows theDanaclassification system[1][26]

which closely parallels theStrunz classification.
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Silicate class

Quartz

The largest group of minerals by far are thesilicates(most rocks are 95% silicates), which are

composed largely ofsiliconandoxygen, with the addition of ions such

asaluminium,magnesium,iron, andcalcium. Some important rock-forming silicates include

thefeldspars,quartz,olivines,pyroxenes,amphiboles,garnets, andmicas.

Carbonate class

Thecarbonate mineralsconsist of those minerals containing the anion (CO3)2

and

includecalciteandaragonite(both calcium carbonate),dolomite(magnesium/calcium carbonate)

andsiderite(iron carbonate). Carbonates are commonly deposited in marine settings when the

shells of deadplanktoniclife settle and accumulate on the sea floor. Carbonates are also found

inevaporiticsettings (e.g. theGreat Salt Lake,Utah) and also inkarstregions, where the

dissolution and reprecipitation of carbonates leads to the formation

ofcaves,stalactitesandstalagmites. The carbonate class also includes thenitrateandborate

minerals.

Sulfate class

Hanksite, Na22K(SO4)9(CO3)2Cl, one of the few minerals that is considered a carbonate and a sulfate

Sulfate mineralsall contain the sulfate anion, SO42

. Sulfates commonly form

inevaporiticsettings where highly saline waters slowly evaporate, allowing the formation of bothsulfates and halides at the water-sediment interface. Sulfates also occur inhydrothermalvein
http://en.wikipedia.org/wiki/Quartzhttp://en.wikipedia.org/wiki/Quartzhttp://en.wikipedia.org/wiki/Silicate_mineralshttp://en.wikipedia.org/wiki/Silicate_mineralshttp://en.wikipedia.org/wiki/Silicate_mineralshttp://en.wikipedia.org/wiki/Siliconhttp://en.wikipedia.org/wiki/Siliconhttp://en.wikipedia.org/wiki/Siliconhttp://en.wikipedia.org/wiki/Oxygenhttp://en.wikipedia.org/wiki/Oxygenhttp://en.wikipedia.org/wiki/Oxygenhttp://en.wikipedia.org/wiki/Aluminiumhttp://en.wikipedia.org/wiki/Aluminiumhttp://en.wikipedia.org/wiki/Aluminiumhttp://en.wikipedia.org/wiki/Magnesiumhttp://en.wikipedia.org/wiki/Magnesiumhttp://en.wikipedia.org/wiki/Magnesiumhttp://en.wikipedia.org/wiki/Ironhttp://en.wikipedia.org/wiki/Ironhttp://en.wikipedia.org/wiki/Ironhttp://en.wikipedia.org/wiki/Calciumhttp://en.wikipedia.org/wiki/Calciumhttp://en.wikipedia.org/wiki/Calciumhttp://en.wikipedia.org/wiki/Feldsparhttp://en.wikipedia.org/wiki/Feldsparhttp://en.wikipedia.org/wiki/Feldsparhttp://en.wikipedia.org/wiki/Quartzhttp://en.wikipedia.org/wiki/Quartzhttp://en.wikipedia.org/wiki/Olivinehttp://en.wikipedia.org/wiki/Olivinehttp://en.wikipedia.org/wiki/Olivinehttp://en.wikipedia.org/wiki/Pyroxenehttp://en.wikipedia.org/wiki/Pyroxenehttp://en.wikipedia.org/wiki/Pyroxenehttp://en.wikipedia.org/wiki/Amphibolehttp://en.wikipedia.org/wiki/Amphibolehttp://en.wikipedia.org/wiki/Amphibolehttp://en.wikipedia.org/wiki/Garnethttp://en.wikipedia.org/wiki/Garnethttp://en.wikipedia.org/wiki/Garnethttp://en.wikipedia.org/wiki/Micahttp://en.wikipedia.org/wiki/Micahttp://en.wikipedia.org/wiki/Micahttp://en.wikipedia.org/wiki/Carbonate_mineralshttp://en.wikipedia.org/wiki/Carbonate_mineralshttp://en.wikipedia.org/wiki/Carbonate_mineralshttp://en.wikipedia.org/wiki/Calcitehttp://en.wikipedia.org/wiki/Calcitehttp://en.wikipedia.org/wiki/Calcitehttp://en.wikipedia.org/wiki/Aragonitehttp://en.wikipedia.org/wiki/Aragonitehttp://en.wikipedia.org/wiki/Aragonitehttp://en.wikipedia.org/wiki/Dolomitehttp://en.wikipedia.org/wiki/Dolomitehttp://en.wikipedia.org/wiki/Dolomitehttp://en.wikipedia.org/wiki/Sideritehttp://en.wikipedia.org/wiki/Sideritehttp://en.wikipedia.org/wiki/Sideritehttp://en.wikipedia.org/wiki/Planktonhttp://en.wikipedia.org/wiki/Planktonhttp://en.wikipedia.org/wiki/Planktonhttp://en.wikipedia.org/wiki/Evaporitehttp://en.wikipedia.org/wiki/Evaporitehttp://en.wikipedia.org/wiki/Evaporitehttp://en.wikipedia.org/wiki/Great_Salt_Lakehttp://en.wikipedia.org/wiki/Great_Salt_Lakehttp://en.wikipedia.org/wiki/Great_Salt_Lakehttp://en.wikipedia.org/wiki/Utahhttp://en.wikipedia.org/wiki/Utahhttp://en.wikipedia.org/wiki/Utahhttp://en.wikipedia.org/wiki/Karsthttp://en.wikipedia.org/wiki/Karsthttp://en.wikipedia.org/wiki/Karsthttp://en.wikipedia.org/wiki/Cavehttp://en.wikipedia.org/wiki/Cavehttp://en.wikipedia.org/wiki/Cavehttp://en.wikipedia.org/wiki/Stalactitehttp://en.wikipedia.org/wiki/Stalactitehttp://en.wikipedia.org/wiki/Stalactitehttp://en.wikipedia.org/wiki/Stalagmitehttp://en.wikipedia.org/wiki/Stalagmitehttp://en.wikipedia.org/wiki/Stalagmitehttp://en.wikipedia.org/wiki/Nitratehttp://en.wikipedia.org/wiki/Nitratehttp://en.wikipedia.org/wiki/Nitratehttp://en.wikipedia.org/wiki/Borate_mineralhttp://en.wikipedia.org/wiki/Borate_mineralhttp://en.wikipedia.org/wiki/Borate_mineralhttp://en.wikipedia.org/wiki/Borate_mineralhttp://en.wikipedia.org/wiki/Hanksitehttp://en.wikipedia.org/wiki/Hanksitehttp://en.wikipedia.org/wiki/Sulfate_mineralhttp://en.wikipedia.org/wiki/Sulfate_mineralhttp://en.wikipedia.org/wiki/Evaporitehttp://en.wikipedia.org/wiki/Evaporitehttp://en.wikipedia.org/wiki/Evaporitehttp://en.wikipedia.org/wiki/Hydrothermalhttp://en.wikipedia.org/wiki/Hydrothermalhttp://en.wikipedia.org/wiki/Hydrothermalhttp://en.wikipedia.org/wiki/File:Hanksite.JPGhttp://en.wikipedia.org/wiki/File:Hanksite.JPGhttp://en.wikipedia.org/wiki/File:Quartz,_Tibet.jpghttp://en.wikipedia.org/wiki/File:Quartz,_Tibet.jpghttp://en.wikipedia.org/wiki/File:Hanksite.JPGhttp://en.wikipedia.org/wiki/File:Hanksite.JPGhttp://en.wikipedia.org/wiki/File:Quartz,_Tibet.jpghttp://en.wikipedia.org/wiki/File:Quartz,_Tibet.jpghttp://en.wikipedia.org/wiki/File:Hanksite.JPGhttp://en.wikipedia.org/wiki/File:Hanksite.JPGhttp://en.wikipedia.org/wiki/File:Quartz,_Tibet.jpghttp://en.wikipedia.org/wiki/File:Quartz,_Tibet.jpghttp://en.wikipedia.org/wiki/File:Hanksite.JPGhttp://en.wikipedia.org/wiki/File:Hanksite.JPGhttp://en.wikipedia.org/wiki/File:Quartz,_Tibet.jpghttp://en.wikipedia.org/wiki/File:Quartz,_Tibet.jpghttp://en.wikipedia.org/wiki/Hydrothermalhttp://en.wikipedia.org/wiki/Evaporitehttp://en.wikipedia.org/wiki/Sulfate_mineralhttp://en.wikipedia.org/wiki/Hanksitehttp://en.wikipedia.org/wiki/Borate_mineralhttp://en.wikipedia.org/wiki/Borate_mineralhttp://en.wikipedia.org/wiki/Nitratehttp://en.wikipedia.org/wiki/Stalagmitehttp://en.wikipedia.org/wiki/Stalactitehttp://en.wikipedia.org/wiki/Cavehttp://en.wikipedia.org/wiki/Karsthttp://en.wikipedia.org/wiki/Utahhttp://en.wikipedia.org/wiki/Great_Salt_Lakehttp://en.wikipedia.org/wiki/Evaporitehttp://en.wikipedia.org/wiki/Planktonhttp://en.wikipedia.org/wiki/Sideritehttp://en.wikipedia.org/wiki/Dolomitehttp://en.wikipedia.org/wiki/Aragonitehttp://en.wikipedia.org/wiki/Calcitehttp://en.wikipedia.org/wiki/Carbonate_mineralshttp://en.wikipedia.org/wiki/Micahttp://en.wikipedia.org/wiki/Garnethttp://en.wikipedia.org/wiki/Amphibolehttp://en.wikipedia.org/wiki/Pyroxenehttp://en.wikipedia.org/wiki/Olivinehttp://en.wikipedia.org/wiki/Quartzhttp://en.wikipedia.org/wiki/Feldsparhttp://en.wikipedia.org/wiki/Calciumhttp://en.wikipedia.org/wiki/Ironhttp://en.wikipedia.org/wiki/Magnesiumhttp://en.wikipedia.org/wiki/Aluminiumhttp://en.wikipedia.org/wiki/Oxygenhttp://en.wikipedia.org/wiki/Siliconhttp://en.wikipedia.org/wiki/Silicate_mineralshttp://en.wikipedia.org/wiki/Quartz


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systems as gangue minerals along withsulfideoreminerals. Another occurrence is as

secondaryoxidationproducts of original sulfide minerals. Common sulfates

includeanhydrite(calcium sulfate),celestine(strontium sulfate),barite(barium sulfate),

andgypsum(hydrated calcium sulfate). The sulfate class also includes

thechromate,molybdate,selenate,sulfite,tellurate, andtungstateminerals.

Halide class

Halite

Thehalide mineralsare the group of minerals forming the naturalsaltsand

includefluorite(calcium fluoride),halite(sodium chloride),sylvite(potassium chloride), andsal

ammoniac(ammonium chloride). Halides, like sulfates, are commonly found inevaporitesettings

such assalt lakesand landlocked seas such as theDead SeaandGreat Salt Lake. The halide

class includes thefluoride,chloride,bromideandiodideminerals.

Oxide class

Oxide mineralsare extremely important inminingas they form many of theoresfrom which

valuable metals can be extracted. They also carry the best record of changes in theEarth's

magnetic field. They commonly occur as precipitates close to the Earth's

surface,oxidationproducts of other minerals in the near surfaceweatheringzone, and as

accessory minerals in igneous rocks of the crust andmantle. Common oxides

includehematite(iron oxide),magnetite(iron oxide),chromite(iron chromium

oxide),spinel(magnesium aluminium oxide a common component of the mantle),ilmenite(iron

titanium oxide),rutile(titanium dioxide), andice(hydrogen oxide). The oxide class includes the

oxide and thehydroxideminerals.

Sulfide class

Manysulfide mineralsare economically important as metalores. Common sulfides

includepyrite(iron sulfide commonly known as fools' gold),chalcopyrite(copper iron

sulfide),pentlandite(nickel iron sulfide), andgalena(lead sulfide). The sulfide class also includes

theselenides, thetellurides, thearsenides, theantimonides, the bismuthinides, and

thesulfosalts(sulfur and a second anion such as arsenic).

Phosphate class

Thephosphate mineralgroup actually includes any mineral with a tetrahedral unit AO4 where A

can bephosphorus,antimony,arsenicorvanadium. By far the most common phosphate
http://en.wikipedia.org/wiki/Sulfidehttp://en.wikipedia.org/wiki/Sulfidehttp://en.wikipedia.org/wiki/Orehttp://en.wikipedia.org/wiki/Orehttp://en.wikipedia.org/wiki/Orehttp://en.wikipedia.org/wiki/Oxidationhttp://en.wikipedia.org/wiki/Oxidationhttp://en.wikipedia.org/wiki/Oxidationhttp://en.wikipedia.org/wiki/Anhydritehttp://en.wikipedia.org/wiki/Anhydritehttp://en.wikipedia.org/wiki/Anhydritehttp://en.wikipedia.org/wiki/Calcium_sulfatehttp://en.wikipedia.org/wiki/Calcium_sulfatehttp://en.wikipedia.org/wiki/Calcium_sulfatehttp://en.wikipedia.org/wiki/Celestine_(mineral)http://en.wikipedia.org/wiki/Celestine_(mineral)http://en.wikipedia.org/wiki/Celestine_(mineral)http://en.wikipedia.org/wiki/Baritehttp://en.wikipedia.org/wiki/Baritehttp://en.wikipedia.org/wiki/Baritehttp://en.wikipedia.org/wiki/Gypsumhttp://en.wikipedia.org/wiki/Gypsumhttp://en.wikipedia.org/wiki/Gypsumhttp://en.wikipedia.org/wiki/Chromatehttp://en.wikipedia.org/wiki/Chromatehttp://en.wikipedia.org/wiki/Chromatehttp://en.wikipedia.org/wiki/Molybdatehttp://en.wikipedia.org/wiki/Molybdatehttp://en.wikipedia.org/wiki/Molybdatehttp://en.wikipedia.org/wiki/Selenatehttp://en.wikipedia.org/wiki/Selenatehttp://en.wikipedia.org/wiki/Selenatehttp://en.wikipedia.org/wiki/Sulfitehttp://en.wikipedia.org/wiki/Sulfitehttp://en.wikipedia.org/wiki/Sulfitehttp://en.wikipedia.org/wiki/Telluratehttp://en.wikipedia.org/wiki/Telluratehttp://en.wikipedia.org/wiki/Telluratehttp://en.wikipedia.org/wiki/Tungstatehttp://en.wikipedia.org/wiki/Tungstatehttp://en.wikipedia.org/wiki/Tungstatehttp://en.wikipedia.org/wiki/Halitehttp://en.wikipedia.org/wiki/Halitehttp://en.wikipedia.org/wiki/Halide_mineralhttp://en.wikipedia.org/wiki/Halide_mineralhttp://en.wikipedia.org/wiki/Halide_mineralhttp://en.wikipedia.org/wiki/Salthttp://en.wikipedia.org/wiki/Salthttp://en.wikipedia.org/wiki/Salthttp://en.wikipedia.org/wiki/Fluoritehttp://en.wikipedia.org/wiki/Fluoritehttp://en.wikipedia.org/wiki/Fluoritehttp://en.wikipedia.org/wiki/Halitehttp://en.wikipedia.org/wiki/Halitehttp://en.wikipedia.org/wiki/Halitehttp://en.wikipedia.org/wiki/Sylvitehttp://en.wikipedia.org/wiki/Sylvitehttp://en.wikipedia.org/wiki/Sylvitehttp://en.wikipedia.org/wiki/Sal_ammoniachttp://en.wikipedia.org/wiki/Sal_ammoniachttp://en.wikipedia.org/wiki/Sal_ammoniachttp://en.wikipedia.org/wiki/Sal_ammoniachttp://en.wikipedia.org/wiki/Evaporitehttp://en.wikipedia.org/wiki/Evaporitehttp://en.wikipedia.org/wiki/Evaporitehttp://en.wikipedia.org/wiki/Salt_lakehttp://en.wikipedia.org/wiki/Salt_lakehttp://en.wikipedia.org/wiki/Salt_lakehttp://en.wikipedia.org/wiki/Dead_Seahttp://en.wikipedia.org/wiki/Dead_Seahttp://en.wikipedia.org/wiki/Dead_Seahttp://en.wikipedia.org/wiki/Great_Salt_Lakehttp://en.wikipedia.org/wiki/Great_Salt_Lakehttp://en.wikipedia.org/wiki/Great_Salt_Lakehttp://en.wikipedia.org/wiki/Fluoridehttp://en.wikipedia.org/wiki/Fluoridehttp://en.wikipedia.org/wiki/Fluoridehttp://en.wikipedia.org/wiki/Chloridehttp://en.wikipedia.org/wiki/Chloridehttp://en.wikipedia.org/wiki/Chloridehttp://en.wikipedia.org/wiki/Bromidehttp://en.wikipedia.org/wiki/Bromidehttp://en.wikipedia.org/wiki/Bromidehttp://en.wikipedia.org/wiki/Iodidehttp://en.wikipedia.org/wiki/Iodidehttp://en.wikipedia.org/wiki/Oxide_mineralhttp://en.wikipedia.org/wiki/Oxide_mineralhttp://en.wikipedia.org/wiki/Mininghttp://en.wikipedia.org/wiki/Mininghttp://en.wikipedia.org/wiki/Mininghttp://en.wikipedia.org/wiki/Oreshttp://en.wikipedia.org/wiki/Oreshttp://en.wikipedia.org/wiki/Oreshttp://en.wikipedia.org/wiki/Earth%27s_magnetic_fieldhttp://en.wikipedia.org/wiki/Earth%27s_magnetic_fieldhttp://en.wikipedia.org/wiki/Earth%27s_magnetic_fieldhttp://en.wikipedia.org/wiki/Earth%27s_magnetic_fieldhttp://en.wikipedia.org/wiki/Oxidationhttp://en.wikipedia.org/wiki/Oxidationhttp://en.wikipedia.org/wiki/Oxidationhttp://en.wikipedia.org/wiki/Weatheringhttp://en.wikipedia.org/wiki/Weatheringhttp://en.wikipedia.org/wiki/Weatheringhttp://en.wikipedia.org/wiki/Mantle_(geology)http://en.wikipedia.org/wiki/Mantle_(geology)http://en.wikipedia.org/wiki/Mantle_(geology)http://en.wikipedia.org/wiki/Hematitehttp://en.wikipedia.org/wiki/Hematitehttp://en.wikipedia.org/wiki/Hematitehttp://en.wikipedia.org/wiki/Magnetitehttp://en.wikipedia.org/wiki/Magnetitehttp://en.wikipedia.org/wiki/Magnetitehttp://en.wikipedia.org/wiki/Chromitehttp://en.wikipedia.org/wiki/Chromitehttp://en.wikipedia.org/wiki/Chromitehttp://en.wikipedia.org/wiki/Spinelhttp://en.wikipedia.org/wiki/Spinelhttp://en.wikipedia.org/wiki/Spinelhttp://en.wikipedia.org/wiki/Ilmenitehttp://en.wikipedia.org/wiki/Ilmenitehttp://en.wikipedia.org/wiki/Ilmenitehttp://en.wikipedia.org/wiki/Rutilehttp://en.wikipedia.org/wiki/Rutilehttp://en.wikipedia.org/wiki/Rutilehttp://en.wikipedia.org/wiki/Icehttp://en.wikipedia.org/wiki/Icehttp://en.wikipedia.org/wiki/Icehttp://en.wikipedia.org/wiki/Hydroxidehttp://en.wikipedia.org/wiki/Hydroxidehttp://en.wikipedia.org/wiki/Hydroxidehttp://en.wikipedia.org/wiki/Sulfide_mineralhttp://en.wikipedia.org/wiki/Sulfide_mineralhttp://en.wikipedia.org/wiki/Sulfide_mineralhttp://en.wikipedia.org/wiki/Orehttp://en.wikipedia.org/wiki/Orehttp://en.wikipedia.org/wiki/Orehttp://en.wikipedia.org/wiki/Pyritehttp://en.wikipedia.org/wiki/Pyritehttp://en.wikipedia.org/wiki/Pyritehttp://en.wikipedia.org/wiki/Chalcopyritehttp://en.wikipedia.org/wiki/Chalcopyritehttp://en.wikipedia.org/wiki/Chalcopyritehttp://en.wikipedia.org/wiki/Pentlanditehttp://en.wikipedia.org/wiki/Pentlanditehttp://en.wikipedia.org/wiki/Pentlanditehttp://en.wikipedia.org/wiki/Galenahttp://en.wikipedia.org/wiki/Galenahttp://en.wikipedia.org/wiki/Galenahttp://en.wikipedia.org/wiki/Selenidehttp://en.wikipedia.org/wiki/Selenidehttp://en.wikipedia.org/wiki/Selenidehttp://en.wikipedia.org/wiki/Telluride_(chemistry)http://en.wikipedia.org/wiki/Telluride_(chemistry)http://en.wikipedia.org/wiki/Telluride_(chemistry)http://en.wikipedia.org/wiki/Arsenidehttp://en.wikipedia.org/wiki/Arsenidehttp://en.wikipedia.org/wiki/Arsenidehttp://en.wikipedia.org/wiki/Antimonidehttp://en.wikipedia.org/wiki/Antimonidehttp://en.wikipedia.org/wiki/Antimonidehttp://en.wikipedia.org/wiki/Sulfosalthttp://en.wikipedia.org/wiki/Sulfosalthttp://en.wikipedia.org/wiki/Sulfosalthttp://en.wikipedia.org/wiki/Phosphate_mineralhttp://en.wikipedia.org/wiki/Phosphate_mineralhttp://en.wikipedia.org/wiki/Phosphate_mineralhttp://en.wikipedia.org/wiki/Phosphorushttp://en.wikipedia.org/wiki/Phosphorushttp://en.wikipedia.org/wiki/Phosphorushttp://en.wikipedia.org/wiki/Antimonyhttp://en.wikipedia.org/wiki/Antimonyhttp://en.wikipedia.org/wiki/Antimonyhttp://en.wikipedia.org/wiki/Arsenichttp://en.wikipedia.org/wiki/Arsenichttp://en.wikipedia.org/wiki/Arsenichttp://en.wikipedia.org/wiki/Vanadiumhttp://en.wikipedia.org/wiki/Vanadiumhttp://en.wikipedia.org/wiki/Vanadiumhttp://en.wikipedia.org/wiki/File:Halite(Salt)USGOV.jpghttp://en.wikipedia.org/wiki/File:Halite(Salt)USGOV.jpghttp://en.wikipedia.org/wiki/File:Halite(Salt)USGOV.jpghttp://en.wikipedia.org/wiki/File:Halite(Salt)USGOV.jpghttp://en.wikipedia.org/wiki/Vanadiumhttp://en.wikipedia.org/wiki/Arsenichttp://en.wikipedia.org/wiki/Antimonyhttp://en.wikipedia.org/wiki/Phosphorushttp://en.wikipedia.org/wiki/Phosphate_mineralhttp://en.wikipedia.org/wiki/Sulfosalthttp://en.wikipedia.org/wiki/Antimonidehttp://en.wikipedia.org/wiki/Arsenidehttp://en.wikipedia.org/wiki/Telluride_(chemistry)http://en.wikipedia.org/wiki/Selenidehttp://en.wikipedia.org/wiki/Galenahttp://en.wikipedia.org/wiki/Pentlanditehttp://en.wikipedia.org/wiki/Chalcopyritehttp://en.wikipedia.org/wiki/Pyritehttp://en.wikipedia.org/wiki/Orehttp://en.wikipedia.org/wiki/Sulfide_mineralhttp://en.wikipedia.org/wiki/Hydroxidehttp://en.wikipedia.org/wiki/Icehttp://en.wikipedia.org/wiki/Rutilehttp://en.wikipedia.org/wiki/Ilmenitehttp://en.wikipedia.org/wiki/Spinelhttp://en.wikipedia.org/wiki/Chromitehttp://en.wikipedia.org/wiki/Magnetitehttp://en.wikipedia.org/wiki/Hematitehttp://en.wikipedia.org/wiki/Mantle_(geology)http://en.wikipedia.org/wiki/Weatheringhttp://en.wikipedia.org/wiki/Oxidationhttp://en.wikipedia.org/wiki/Earth%27s_magnetic_fieldhttp://en.wikipedia.org/wiki/Earth%27s_magnetic_fieldhttp://en.wikipedia.org/wiki/Oreshttp://en.wikipedia.org/wiki/Mininghttp://en.wikipedia.org/wiki/Oxide_mineralhttp://en.wikipedia.org/wiki/Iodidehttp://en.wikipedia.org/wiki/Bromidehttp://en.wikipedia.org/wiki/Chloridehttp://en.wikipedia.org/wiki/Fluoridehttp://en.wikipedia.org/wiki/Great_Salt_Lakehttp://en.wikipedia.org/wiki/Dead_Seahttp://en.wikipedia.org/wiki/Salt_lakehttp://en.wikipedia.org/wiki/Evaporitehttp://en.wikipedia.org/wiki/Sal_ammoniachttp://en.wikipedia.org/wiki/Sal_ammoniachttp://en.wikipedia.org/wiki/Sylvitehttp://en.wikipedia.org/wiki/Halitehttp://en.wikipedia.org/wiki/Fluoritehttp://en.wikipedia.org/wiki/Salthttp://en.wikipedia.org/wiki/Halide_mineralhttp://en.wikipedia.org/wiki/Halitehttp://en.wikipedia.org/wiki/Tungstatehttp://en.wikipedia.org/wiki/Telluratehttp://en.wikipedia.org/wiki/Sulfitehttp://en.wikipedia.org/wiki/Selenatehttp://en.wikipedia.org/wiki/Molybdatehttp://en.wikipedia.org/wiki/Chromatehttp://en.wikipedia.org/wiki/Gypsumhttp://en.wikipedia.org/wiki/Baritehttp://en.wikipedia.org/wiki/Celestine_(mineral)http://en.wikipedia.org/wiki/Calcium_sulfatehttp://en.wikipedia.org/wiki/Anhydritehttp://en.wikipedia.org/wiki/Oxidationhttp://en.wikipedia.org/wiki/Orehttp://en.wikipedia.org/wiki/Sulfide


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isapatitewhich is an importantbiologicalmineral found in teeth and bones of many animals. The

phosphate class includes the phosphate,arsenate,vanadate, andantimonateminerals.

Element class

The elemental group includesnative metalsandintermetallicelements

(gold,silver,copper),semi-metalsandnon-metals(antimony,bismuth,graphite,sulfur). Thisgroup also includes naturalalloys, such aselectrum(a natural alloy of gold and

silver),phosphides,silicides,nitridesandcarbides(which are usually only found naturally in a few

raremeteorites).

Organic class

The organic mineral class includesbiogenicsubstances in which geological processes have been

a part of the genesis or origin of the existing compound.[2]

Minerals of the organic class include

variousoxalates,mellitates,citrates,cyanates,acetates,formates,hydrocarbonsand other

miscellaneous species.[5]

Examples

includewhewellite,moolooite,mellite,fichtelite,carpathite,evenkiteandabelsonite.

rocks

There are three kinds of rocks that can be found on Earth. These rocks are the Igneous,the Sedimentary and the Metamorphic rocks. These kinds ofrocks differ from their origin.

The Igneous rock is formed from the cooling and hardening of themoltenmaterials that are found in the crust, either closer to the surface or near avolcano. This kind of rock is the most abundant rock on the planet, comprising about

65% of allthe rocks.

Igneous is hard and tough, this rock are further divided into two groups; the extrusiveigneous rock and the intrusive igneous rock.

The common igneous rocks are the Diorite, the Andesite, the Granite, the Gabbro, theObsidian and the Basalt.

Diorite is a coarse-grained and generally light-colored rock. It is a kind of intrusive rockthat cools very slowly. Andesite is a fine-grained and light-colored extrusive rock and itis formed in the lava flows. Granite is a light-colored usually in gray or in pink and

coarse-grained rock and made up of several kinds of crystals. The Gabbro is a kind of acoarse-grained rock and it is often called as the black granite. The Obsidian is a dark-glassy this rock has no crystals. The Basalt is a dark and fine-grained rock that is formedfrom the lava or magma near the surface of the Earth.

The extrusive igneous rock is formed when the magma reach thesurface and hardens. Itis generally dark in color and heavy. This is because the extrusive igneous rock is reachin magnesium as well as in iron.

The intrusive igneous rock is formed when the magma finds its way to the crust but doesnot reach the surface. It cools slowly and takes thousands or millions of years to harden.The intrusive igneous rock is generally light-colored; it is rich in silica and it has a large

crystals. The igneous rock that has a big crystals are described as coarse-grained; whilethe igneous rock that has small crystals are described as fine-grained.
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The Sedimentary rock is formed from the other rocks and was deposited by the waterand air. It is considered as the third in numbers among the three kinds of rocks whichcomprise about 8% of all the rocks.

This rock is exposed to the air, to the water, to the sunlight and to some acids in theenvironment. Some of this rock may contain the remains or traces of some living thingssuch as fishes, the shells, plants or mammals. These remains of the living organisms

that can be found on the sedimentary rocks are called as fossils.

The sedimentary rock is in different types. The most common of these are theconglomerate, the sandstone, the shale, the limestone and the gypsum.

The conglomerate is consists of pebbles or by pieces of gravel that are cemented

together. This type of igneous rock is usually formed in the riverbeds, in the foot of themountain or along the beaches.

The sandstone is formed when the layers of sand grains are deposited by the water or by

the wind. This will eventually packed and become cemented together.

The shale is considered as the most common type of sedimentary rock; it makes 50% ofrock that are exposed on Earth. The shale is hardened clay.

The limestone is a kind of sedimentary rock that is mostly composed of calcium

carbonate. Limestone is formed from the actions of the plants and animals in the bottomof the lakes and the oceans.

The gypsum is the kind of sedimentary rock that is formed when the hydrated calcium

sulfate in the seawater settles.

The Metamorphic rock is formed when the igneous rock or the sedimentary rock changein color in texture and on its crystal structure because of a great pressure as well astemperature. This kind of rock is considered as the second most abundant rock

comprising about 27% of all the rocks.

The most common types of the metamorphic rocks are the marble, the gneiss and thequartzite.

The marble is considered as the most widely known among the metamorphic rocks. It is

formed from the limestone but it is denser and harder. The gneiss rock is formed fromthe conglomerate or granite while the quartzite rock is formed from the sandstone; it is

heavy, hard and nonporous. It has also a grainy texture.

rock, in geology, naturally occurring and coherent aggregate of one or more minerals. Such

aggregates constitute the basic unit of which the solid Earthis comprised and typically form recognizable and

mappable volumes. Rocks are commonly divided into three major classes according to the processes that

resulted in their formation. These classes are (1) igneous rocks, which have solidified from molten material called

magma; (2) sedimentary rocks, those consisting of fragments derived from preexisting rocks or of materials

precipitated from solutions; and (3) metamorphic rocks, which have been derived from either igneous or
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sedimentary rocks under conditions that caused changes in mineralogical composition, texture, and internal

structure. These three classes, in turn, are subdivided into numerous groups and types on the basis of various

factors, the most important of which are chemical, mineralogical, and textural attributes.

General considerationsRock types

Igneous rocksare those that solidify frommagma, a molten mixture of rock-

forming minerals and usually volatiles such as gases and steam. Since their

constituent minerals are crystallized from molten material, igneous rocks are formed

at high temperatures. They originate from processes deep within the Earthtypically

at depths of about 50 to 200 kilometres (30 to 120 miles)in the mid- to lower-crust

or in theupper mantle. Igneous rocks are subdivided into twocategories:intrusive(emplaced in the crust), and extrusive (extruded onto the surface

of the land or ocean bottom), in which case the cooling molten material is calledlava.

Sedimentary rocksare those that are deposited and lithified (compacted and cemented

together) at the Earths surface, with the assistance of running water, wind, ice, or

living organisms. Most are deposited from the land surface to the bottoms of lakes,

rivers, and oceans. Sedimentary rocks are generally stratifiedi.e., they have

layering. Layers may be distinguished by differences in colour, particle size, type of

cement, or internal arrangement.

Metamorphic rocksare those formed by changes in preexisting rocks under the

influence of hightemperature,pressure, and chemically active solutions. The changes

can be chemical (compositional) and physical (textural) in character. Metamorphic

rocks are often formed by processes deep within the Earth that produce

new minerals, textures, and crystal structures. Therecrystallizationthat takesplacedoes

so essentially in thesolid state, rather than by complete remelting, and can be aided

by ductile deformation and the presence ofinterstitial fluidssuch as water.

Metamorphism often produces apparent layering, or banding, because of

thesegregationof minerals into separate bands.Metamorphic processescan also occur at

the Earths surface due tometeoriteimpact events and pyrometamorphism taking

place near burningcoal seamsignited by lightning strikes.
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Rock cycle

Geologic materialsmineral crystals and theirhost rocktypesare

cycled through various forms. The process depends on temperature, pressure, time,

and changes in environmental conditions in theEarths crustand at its surface. The

rock cycle illustrated in Figure 1 reflects the basic relationships among

igneous, metamorphic, and sedimentary rocks.Erosionincludes weathering

(the physical and chemical breakdown of minerals) and transportation to a site of

deposition.Diagenesisis, as previously explained, the process of formingsedimentary

rockbycompactionand naturalcementationof grains, orcrystallizationfrom water or

solutions, or recrystallization. The conversion ofsedimentto rock is termedlithification.

Abundance of rock types

An estimate of the distribution of rock types in large structural units of the terrestrial

crust is given in the Table. Therelative abundanceof main rock types andminerals in the

crust is shown in the Table.
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Texture

The texture of a rock is the size, shape, and arrangement of the grains

(for sedimentary rocks) orcrystals(for igneous and metamorphic rocks). Also of

importance are the rocks extent ofhomogeneity(i.e., uniformity of composition

throughout) and the degree ofisotropy. The latter is the extent to which the

bulkstructure and composition are the same in all directions in the rock.

Analysis of texture can yield information about the rocks source material, conditions

and environment of deposition (for sedimentary rock) or crystallization and

recrystallization (for igneous andmetamorphic rock, respectively), and subsequentgeologic history and change.
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Classification bygrainor crystal size

The common textural terms used for rock types with respect to the size of the grains

or crystals, are given in the Table. The particle-size categories are

derived from the Udden-Wentworth scale developed for sediment. For igneous

and metamorphic rocks, the terms are generally used as modifierse.g., medium-

grainedgranite.Aphaniticis a descriptive term for small crystals, andphaneriticfor larger

ones. Very coarse crystals (those larger than 3 centimetres, or 1.2 inches) are

termed pegmatitic.

For sedimentary rocks, the broad categories of sediment size are coarse (greater

than 2 millimetres, or 0.08 inch), medium (between 2 and 1/16 millimetres), and fine

(under 1/16 millimetre). The latter includessiltandclay, which both have a size

indistinguishable by the human eye and are also termeddust. Mostshales(the lithified

version of clay) contain some silt.Pyroclastic rocksare those formed from clastic (from

the Greek word for broken) material ejected from volcanoes.Blocksare fragments

broken from solid rock, whilebombsare molten when ejected.Porosity

The term rock refers to the bulk volume of the material, including the grains or

crystals as well as the contained void space. The volumetric portion of bulk rock that

is not occupied by grains, crystals, or natural cementing material is termedporosity.

That is to say, porosity is the ratio of void volume to the bulk volume (grains plus void

space). This void space consists ofporespace between grains or crystals, in addition

to crack space. In sedimentary rocks, the amount of pore space depends on the

degree of compaction of the sediment (with compaction generally increasing with

depth of burial), on thepackingarrangement and shape of grains, on the amount of

cementation, and on the degree ofsorting. Typical cements are siliceous, calcareous

or carbonate, or iron-bearing minerals.

Sorting is the tendency of sedimentary rocks to have grains that are similarly sized

i.e., to have a narrow range of sizes (see Figure 2). Poorly sorted

sediment displays a wide range of grain sizes and hence has decreased porosity.

Well-sorted indicates a grain size distribution that is fairly uniform. Depending on the

type of close-packing of the grains, porosity can be substantial. It should be noted
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that in engineering usagee.g., geotechnical orcivil engineeringthe terminology is

phrased oppositely and is referred to asgrading. A well-graded sediment is a

(geologically) poorly sorted one, and a poorly graded sediment is a well-sorted one.

Total porosity encompasses all the void space, including those pores that areinterconnected to the surface of the sample as well as those that are sealed off by

natural cement or other obstructions. Thus the total porosity (T) is

where VolG is the volume of grains (and cement, if any) and VolB is the total bulk

volume. Alternatively, one can calculate T from the measured densities of the bulk

rock and of the (mono)mineralic constituent. Thus,

where Bis the density of the bulk rock and G is the density of the grains

(i.e., themineral, if the composition is monomineralogic and homogeneous). For

example, if asandstonehas a B of 2.38 grams per cubic centimetre (g/cm3) and is

composed of quartz (SiO2) grains having G of 2.65 g/cm3, the total porosity is

Apparent (effective, or net) porosity is the proportion of void space that excludes

the sealed-off pores. It thus measures the pore volume that is effectively

interconnected and accessible to the surface of the sample, which is important when

considering the storage and movement of subsurface fluids such as petroleum,

groundwater, or contaminated fluids.

Physical properties

Physical properties of rocks are of interest and utility in many fields of work, includinggeology, petrophysics, geophysics,materials science, geochemistry, andgeotechnical

engineering. The scale of investigation ranges from the molecular and crystalline up to

terrestrial studies of the Earth and other planetary bodies.Geologistsare interested in

the radioactive age dating of rocks to reconstruct the origin of mineral

deposits;seismologistsformulate prospective earthquake predictions using

premonitory physical or chemical changes;crystallographersstudy the synthesis of

minerals with special optical or physical properties;

explorationgeophysicistsinvestigate the variation of physical properties of subsurface
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rocks to make possible detection of natural resources such as oil and gas,geothermal

energy, and ores of metals;geotechnical engineersexamine the nature and behaviour of

the materials on, in, or of which such structures as buildings, dams, tunnels, bridges,

and underground storage vaults are to be constructed;solid-state physicistsstudy themagnetic, electrical, and mechanical properties of materials for electronic devices,

computer components, or high-performance ceramics; and

petroleumreservoirengineers analyze the response measured on well logs or in the

processes of deep drilling at elevated temperature and pressure.

Since rocks are aggregates of mineral grains or crystals, their properties are

determined in large part by the properties of their various constituent minerals. In a

rock these general properties are determined by averaging the relative properties

and sometimes orientations of the various grains or crystals. As a result, some

properties that are anisotropic (i.e., differ with direction) on a submicroscopic or

crystalline scale are fairly isotropic for a large bulk volume of the rock. Many

properties are also dependent on grain or crystal size, shape, and packing

arrangement, the amount and distribution of void space, the presence of natural

cements in sedimentary rocks, the temperature and pressure, and the type and

amount of contained fluids (e.g., water, petroleum, gases). Because many rocks

exhibit a considerable range in these factors, the assignment of representative

values for a particular property is often done using a statistical variation.

Some properties can vary considerably, depending on whether measured in situ (in

place in the subsurface) or in the laboratory under simulated conditions.

Electricalresistivity, for example, is highly dependent on the fluid content of the rock in

situ and the temperature condition at the particular depth.Density

Density varies significantly among different rock types because of differences inmineralogy and porosity. Knowledge of the distribution of underground rock densities

can assist in interpreting subsurface geologic structure and rock type.

In strict usage, density is defined as the mass of a substance per unit volume;

however, in common usage, it is taken to be theweightin air of a unit volume of a

sample at a specific temperature. Weight is the force that gravitation exerts on a

body (and thus varies with location), whereasmass(a measure of thematterin a body)

is a fundamental property and is constant regardless of location. In routine density

measurements of rocks, the sample weights are considered to be equivalent to their
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masses, because the discrepancy between weight and mass would result in less

error on the computed density than the experimental errors introduced in the

measurement of volume. Thus, density is often determined using weight rather than

mass. Density should properly be reported in kilograms per cubic metre (kg/m3

), butis still often given in grams per cubic centimetre (g/cm3).

Another property closely related to density isspecific gravity. It is defined, as noted

above, as the ratio of the weight or mass in air of a unit volume of material at a

stated temperature to the weight or mass in air of a unit volume of distilled water at

the same temperature. Specificgravityis dimensionless (i.e., has no units).

Thebulk densityof a rock is B = WG/VB, where WG is the weight of grains (sedimentary

rocks) or crystals (igneous and metamorphic rocks) and natural cements, if any,

and VB is the total volume of the grains or crystals plus the void (pore) space. The

density can be dry if the pore space is empty, or it can be saturated if the pores are

filled with fluid (e.g., water), which is more typical of the subsurface (in situ) situation.

If there is pore fluid present,

where Wfl is the weight of pore fluid. In terms of total porosity, saturated density is

and thus

where fl is the density of the pore fluid. Density measurements for a given specimen

involve the determination of any two of the following quantities: pore volume, bulk

volume, or grain volume, along with the weight.

A useful way to assess the density of rocks is to make a histogram plot of the

statistical range of a set of data. The representative value and its variation can be

expressed as follows: (1) mean, the average value, (2) mode, the most common

value (i.e., the peak of the distribution curve), (3) median, the value of the middle

sample of thedata set(i.e., the value at which half of the samples are below and half

are above), and (4)standard deviation, a statistical measure of the spread of the data

(plus and minus one standard deviation from the mean value includes about two-

thirds of the data).

A compilation of dry bulk densities for various rock types found in the upper crust of

the Earth is listed in the Table. A histogram plot of these data, giving the percent of
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the samples as a function of density is shown in Figure 3. The

parameters given include (1) sample division, the range of density in one data

columne.g., 0.036 g/cm3 for Figure 3, (2) number of samples, and (3) standard

deviation. The small inset plot is the percentage of samples (on the vertical axis) that

lie within the interval of the mode -x to the mode +x, wherex is the horizontal

axis.

Dry bulk densities for various rock types

rock type number ofsamples mean (gramsper cubic cm) standarddeviation mode (gramsper cubic cm) median (gramsper cubic cm)

all rocks 1,647 2.73 0.26 2.65 2.86

andesite 197 2.65 0.13 2.58 2.66

basalt 323 2.74 0.47 2.88 2.87

diorite 68 2.86 0.12 2.89 2.87

dolerite

(diabase)224 2.89 0.13 2.96 2.90

gabbro 98 2.95 0.14 2.99 2.97

granite 334 2.66 0.06 2.66 2.66

quartz

porphyry

76 2.62 0.06 2.60 2.62

rhyolite 94 2.51 0.13 2.60 2.49

syenite 93 2.70 0.10 2.67 2.68

trachyte 71 2.57 0.10 2.62 2.57

sandstone 107 2.22 0.23 2.22 2.22

Source: After data from H.S. Washington (1917) and R.J. Piersol, L.E. Workman, and M.C. Watson (1940) as compiled
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by Gary R. Olhoeft and Gordon R. Johnson in Robert S. Carmichael, ed., Handbook of Physical Properties of Rocks, vol. III,

CRC Press, Inc. (1984).

Question: What Is the Most Abundant Element?

Answer: The most abundant element in the universe is hydrogen, which makes up about 3/4 of all matter! Helium makes upmost of the remaining 25%. Oxygen is the third most abundant element in the universe. All of the other elements are

relatively rare.

The chemical composition of the earth is quite a bit different from that of the universe. The most abundant element in the

earth's crust is oxygen, making up 46.6% of the earth's mass. Silicon is the second most abundant element (27.7%), followed

by aluminum (8.1%), iron (5.0%), calcium (3.6%), sodium (2.8%), potassium (2.6%). and magnesium (2.1%). These eight

elements account for approximately 98.5% of the total mass of the earth's crust. Of course, the earth's crust is only the outer

portion of the earth. Future research will tell us about the composition of the mantle and core.

This table shows the chemical composition or abundance of chemical compounds in the Earth's crust. As you can see, the

most comm

7 earth materials

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