A mineral is a naturally occurring, typically inorganic substance with a specific chemical composition and structure. An unknown mineral usually can be identified according to known characteristics of specific minerals in terms of certain parameters that include its appearance, its hardness, and the ways it breaks apart when fractured. Minerals are not to be confused with rocks, which are typically aggregates of minerals. There are some 3,700 varieties of mineral, a handful of which are abundant and wide-ranging in their application. Many more occur less frequently but are extremely important within a more limited field of uses.

1) Elements (carbon [diamond], sulfur, zinc, gold, etc.)

2) Halides (element and halogen, such as chlorine, bromine, or iodine; one example is table salt [sodium chloride]

3) Oxides (element and oxygen, e.g. hematite [iron oxide])

4) Sulfides (element and sulfur, e.g. pyrite [iron sulfide], galena [lead sulfide])

5) Elements and complex ions (ion not just a single charged atom), common examples are:                   

a) Carbonates (CO32-) (calcite, egg shells)                 b) Sulfates (SO42-) (gypsum)                 c) Silicates (SiO44-) (feldspar, quartz)

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

Talc Mg3Si4O10(OH)2 Gypsum CaSO4·2H2O Calcite CaCO3 Fluorite CaF2 Apatite

Ca5(PO4)3(OH,Cl,F) Orthoclase KAlSi3O8 Quartz SiO2 Topaz Al2SiO4(OH,F)2 Corundum Al2O3 Diamond C (pure carbon)

2.Lustre: indicates the way a mineral's surface interacts with light and can range from dull to glassy (vitreous).

Examples:

•Metallic

•Sub-metallic

•Non-metallic

Adamantine – (brilliant) diamond

Vitreous -the luster of a broken glass quartz

Pearly - iridescent and pearl-like apophyllite

Resinous - the luster of resin sphalerite

Silky - a soft light shown by fibrous materials

gypsum

Dull/earthy -shown by finely crystallized minerals

hamatite

3.Color indicates the appearance of the mineral in reflected light or transmitted light for translucent minerals

4.Streak refers 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.

6.Fracture describes how a mineral breaks when broken contrary to its natural cleavage planes

5.Cleavage describes the way a mineral may split apart along various planes. In thin sections, cleavage is visible as thin parallel lines across a mineral.

quartz - made completely of silica tetrahedrons; hardest common mineral

feldspar - most abundant family of minerals in earth’s crust, includes:**potassium feldspar - most common example is orthoclase

**sodium-calcite (plagioclase) feldspars - examples include albite & oligoclase

mica - soft, flaky mineral; includes muscovite (silvery white) and biotite (dark - brown/black)

talc - softest mineral; 1 on the Moh’s scale

amphiboles - most common example is hornblende (dark; shiny; long slender crystals)

pyroxenes - most common example is augite (dark; less luster than horneblende; stubby crystals)

olivine - olive-green; hard (about 6.5); found in dark crystalline rock

garnet - very hard (6.5 - 7.5); found in many crystalline rocks

kaolin - aluminum silicate; forms from weathering of feldspars & other silicates; primary mineral in clay & shale

ferromagnesian silicates: dark colored minerals containing iron & magnesium; may belong to almost any of the silicate families; examples include hornblende, augite, olivine