Chapter 3Chapter 3

MineralsMinerals

Section 3-1 H.W. pg 66 ques.1-4 Section 3-1 H.W. pg 66 ques.1-4 & pg 84 ques. 2,4,8,11,12,15& pg 84 ques. 2,4,8,11,12,15

• Minerals are very important in everyday life. Minerals, bricks, and glass are some examples of how we use minerals.

• Mineral- is a naturally occurring, inorganic solid with a definite chemical composition and an orderly arrangement of atoms.

• There are about 4,000 minerals on Earth.

Mineral CharacteristicsMineral Characteristics

1) All minerals are formed by natural processes. These processes occur on or inside the Earth with no human interaction.

Ex: Salt forms by the natural evaporation of salt water. This type of salt comes from a mineral called Halite.

Salt water solution made in a lab is not a mineral.

Mineral CharacteristicsMineral Characteristics2) Minerals are inorganic- this means that

there is no Carbon is present in minerals.

3) Every mineral is an element or compound with a definite chemical composition.

4) All minerals are crystalline solids. And all crystals have a definite volume and shape.

CrystalsCrystals

• Crystal atoms are arranged in a pattern that is repeated over and over again.

Ex: Graphite atoms are arranged in layers.

Opal- is not a mineral because it has no repeated atom patterns.

Structure of MineralsStructure of Minerals• All minerals are crystalline solids.• Crystalline solids- are solids in which the

atoms are arranged in an orderly repeated fashion.

• This does not mean that all minerals look like crystals.

Ex: Rose quartz doesn’t look like a crystal because it develops in tight spaces.

Clear quartz forms in open spaces and its appearance is clearly crystal shaped.

Crystal vs. Non-CrystalCrystal vs. Non-Crystal

Crystal FormationCrystal Formation

• Crystals form in two ways:1) From cooling Magma2) Could form in solution

Mineral formation from MagmaMineral formation from Magma• Magma is hot melted rock material, that cools

when it reaches the Earth’s surface. However in some cases it could cool before it

reaches the surface.

When magma cools its atoms lose heat and energy. When this happens the atoms move closer together and begin to form compounds.

During this cooling period is when atoms of minerals begin to form repeating patterns.

Crystal Formation from MagmaCrystal Formation from Magma

The type of atoms present and the amount will determine what mineral is produced.

• When magma cools slowly large crystals form.

• When magma cools quickly then small crystals form.

Crystal Formation from SolutionCrystal Formation from Solution• Crystals form minerals dissolved in water.

• When water evaporates, ions are left behind that can combine to form crystals like halite. (salt)

• Or • If there is too much substance in solution

the crystals could form in the solution

SilicatesSilicates

• The most common rock forming minerals belong to a group called the silicates.

• Silicates are minerals that contain the elements O and Si (oxygen and silicon)

• These two elements combine the rocks of the Earth’s crust and mantle.

• Ex: of Silicates are Quartz and Feldspar

Quartz and Feldspar PicsQuartz and Feldspar Pics

How to Identify MineralsHow to Identify MineralsSection 3-2 H.W. pg. 72 ques. 1-4 Section 3-2 H.W. pg. 72 ques. 1-4

& pg. 84 ques. 1,3,5,7,10,13,14,16,17& pg. 84 ques. 1,3,5,7,10,13,14,16,17

• We identify minerals by some very specific physical features and properties.

Color is one way to tell the difference between two minerals but color alone is not enough.

Ex: Gold and pyrite both have the same color, but they are two very different minerals. Pyrite has very little value compared to gold.

So to tell these two apart you have to look at other properties.

Gold and PyriteGold and Pyrite

5 Major properties used to 5 Major properties used to distinguish between mineralsdistinguish between minerals

1) Hardness2) Luster3) Specific gravity4) Streak5) Cleavage/ fracture

5 major properties5 major properties

1) Hardness- This is the measure of how easily a mineral can be scratched.

Ex: Talc, a very soft mineral can be scratched with just your finger nail.

Hardness of MineralsHardness of Minerals

• Diamonds, on the other hand are the hardest mineral.

• The only this that can scratch a diamond is another diamond.

• Remember scratch and break are not the same. If hit hard enough a diamond will shatter.

Mohs ScaleMohs Scale• In 1812 the Mohs scale of mineral hardness was devised by the

German mineralogist Frederich Mohs (1773-1839), who selected the ten minerals because they were common or readily available. The scale is not a linear scale, but somewhat arbitrary.

Hardness of some other items:• 2.5 Fingernail• 2.5–3 Gold, Silver• 3 Copper penny• 4-4.5 Platinum• 4-5 Iron• 5.5 Knife blade• 6-7 Glass• 6.5 Iron pyrite• 7+ Hardened steel file

5 major properties5 major properties

2) Luster- This is the way a mineral reflects light.

This reflection could be metallic, meaning it shines like a metal, or non-metallic or dull or glassy looking.

LusterLuster

5 major properties5 major properties3) Specific Gravity- This is the ratio of the

minerals weight compared to the weight of an equal volume of water.

Ex: Specific Gravity of Gold is 19:1 or 19.This means that gold is 19x heavier that

water.How could you find out the volume of a

solid?

5 major properties5 major properties4) Streak- Is the color of a mineral when it is in

powder form.So if we have a solid mineral we would streak it

across a piece of porcelain to see what color is left behind.

5 major properties5 major properties5) Cleavage/ Fracture- this is the way a mineral

breaks.Minerals that break along a smooth flat surface

have cleavage.

5 major properties5 major properties• Cleavage/ Fracture- Minerals that break

unevenly, or with rough jagged surfaces have fracture.

Other unique propertiesOther unique properties

• Magnetite- is attracted to metal like a magnet.

Other unique propertiesOther unique properties

• Calcite- When light passes through this mineral 2 rays form and it allows you to see a double image.

• Also when you add HCl to it fizzes.

Uses of MineralsUses of MineralsSection 3-3 H.W. pg 84 ques. 6,9 & pg. 86 ques. 6,7-10Section 3-3 H.W. pg 84 ques. 6,9 & pg. 86 ques. 6,7-10

• Gems- Gems are highly prized minerals due to their rareness and beauty.

• They are clearer brighter and more colorful then common minerals.

• Gems always come from other minerals.

• Ex: Amethyst is a gem that comes from Quartz. Because it has less iron in it than quartz does it has a beautiful purple color.

Some important gems Taken from Some important gems Taken from Minerals are:Minerals are:

• Emeralds from Beryl• Ruby from Spinel• Blue Sapphire from CorundumMore are on the chart on pg. 75Some gems are more prized than others.Cullinan Diamond- The largest diamond ever

found. (3,106 karats)Hope Diamond- Owned by Henry Philip Hope.

(45.5 karats)

Useful GemsUseful Gems• Some gems are very useful like diamonds.

• They are not only used to make beautiful jewelry but since they are the hardest mineral on Earth they are also used for cutting tools like saw blades.

• Rubies are used to create lasers.• Quartz is used in watches and clocks.

Useful elements that are found in Useful elements that are found in mineralsminerals

• Gems are the most popular use of minerals but they are not the most important. We use minerals for other very important uses.

1) Ores- An ore is a mineral or rock that contains a useful substance that can be mined.

Iron ore is used in almost everything from frying pans to ships and it comes from the mining of the minerals Hematite & Magnetite.

Useful elements that are found in Useful elements that are found in mineralsminerals

• Aluminum- is mined from Bauxite as aluminum oxide powder.

We make the powder in things like aluminum sheets by a process called smelting or melting at very high temps.

We use aluminum in soda cans, siding for homes, air planes, baseball bats.

Useful elements that are found in Useful elements that are found in mineralsminerals

2) Vein Minerals- mineral deposits left behind that fill the open spaces of rocks.

Under certain conditions minerals dissolve in solution. This mineral/water mixture will travel through weak cracks in rocks and be deposited in these spaces.

Vein MineralsVein Minerals

• Sometimes vein mineral deposits fill in empty spaces after rocks collapse.

Ex: Sphalerite, which comes from zinc and is used in batteries.

Useful elements that are found in Useful elements that are found in mineralsminerals

3) Minerals that contain Titanium- Titanium is a durable, light weight, metallic element that derived from rutile and ilmenite.

We use titanium in car bodies planes, eyeglass frames, tennis rackets, bikes and wheel chairs.

Test on Chapter 3 in one Test on Chapter 3 in one week!!!!!!week!!!!!!