Minerals

What is a Mineral?What is a Mineral?

Naturally-formed Naturally-formed solidsolid substance substance with a with a crystalcrystal structure structure

Pyromorphite

What do all minerals What do all minerals have in common?have in common?

All:All:1.1. Are formed by Are formed by naturalnatural processes. processes.

2.2. Are Are NOTNOT alive and NEVER were alive alive and NEVER were alive

3.3. Have a Have a definitedefinite volume and shape volume and shape

4.4. Are elements or compounds with a Are elements or compounds with a uniqueunique chemical makeupchemical makeup

5.5. Are made up of particles that are arranged Are made up of particles that are arranged in a pattern that is repeated over and over in a pattern that is repeated over and over (called a (called a CRYSTALCRYSTAL))

Watch “Crystals” by Brainpop…

1.What element are diamonds made from?

2. What do all crystals have in common?

Groups of MineralsGroups of Minerals

Minerals are grouped by the Minerals are grouped by the elements they are made of.elements they are made of.

Amethyst

Beryl (Emerald) Calcite

Mineral GroupMineral Group CharacteristicsCharacteristics ExamplesExamples

SilicatesSilicates

Contain Contain oxygenoxygen & & silicasilicaThe most The most abundantabundant group of group of mineralsminerals

Quartz, micaQuartz, mica

MICA Quartz

Mineral GroupMineral Group CharacteristicsCharacteristics ExamplesExamples

Non-SilicatesNon-Silicates

Make up only Make up only 5%5% of the of the Earth’s crustEarth’s crustInclude some Include some of the most of the most important important mineralsminerals

iron, copper, iron, copper, gold, silver, gold, silver, diamonds, diamonds, rubiesrubies

Silver

GoldRuby Iron

Copper

Diamond

Mineral GroupMineral Group CharacteristicsCharacteristics ExamplesExamples

CarbonatesCarbonates Carbon & Carbon & oxygen and a oxygen and a positive ion, positive ion, such as such as calciumcalcium

Calcite Calcite (CaCO(CaCO33))

Calcite with Duftite inclusions

Mineral GroupMineral Group CharacteristicsCharacteristics ExamplesExamples

OxidesOxides Metallic ion Metallic ion and oxygenand oxygen

Hematite Hematite (Fe(Fe22)O)O33

Mineral GroupMineral Group CharacteristicsCharacteristics ExamplesExamples

SulfidesSulfides Sulfur and a Sulfur and a metallic ionmetallic ion

Galena (PbS)Galena (PbS)

Mineral GroupMineral Group CharacteristicsCharacteristics ExamplesExamples

Sulfates Metallic ion, Sulfur & oxygen

Barite (BaSO4)

Barite on Calcite BaSo4 / CaCO3

BariteBaSo4

Mineral GroupMineral Group CharacteristicsCharacteristics ExamplesExamples

Native Elements

Single elements

Gold (Au), Diamond (C), Silver (Ag)

How do minerals form?How do minerals form?

1) Cooling of 1) Cooling of magmamagma (hot, (hot, liquid liquid rockrock and minerals inside the earth and minerals inside the earth (from the mantle))(from the mantle)) Fast Cooling = No Crystals (mineraloids)Fast Cooling = No Crystals (mineraloids) Medium Cooling = small crystalsMedium Cooling = small crystals Slow Cooling = large crystalsSlow Cooling = large crystals

How do minerals form?How do minerals form?

2) Elements dissolved in 2) Elements dissolved in liquidsliquids (usually water)(usually water)

Physical Properties of MineralsPhysical Properties of Minerals (can be used to identify the mineral)(can be used to identify the mineral)

ColorColor Can be misleading Can vary with the type of impurities

Physical Properties of MineralsPhysical Properties of Minerals (can be used to identify the mineral)(can be used to identify the mineral)

LusterLuster Surface reflection metallic = shiny

like metal non-metallic =

dull, non-shiny surface

Pyrite has a metallic luster

Calcite has a non-metallic luster

Physical Properties of Minerals (can be used to identify the mineral)

StreakStreak The color of the powdered

form of the mineral The color of the streak can

be different than the mineral Minerals must be softer than

the streak plate

Streak…can help identify Streak…can help identify quartzquartz

http://www.childrensmuseum.org/geomysteries/cube/b3.html

Physical Properties of MineralsPhysical Properties of Minerals (can be used to identify the mineral)(can be used to identify the mineral)

HardnessHardness How easily a mineral How easily a mineral scratchesscratches

materialsmaterials Mohs Hardness ScaleMohs Hardness Scale

Scale from 1 (Scale from 1 (softestsoftest) to 10 () to 10 (hardesthardest)) Test by seeing if the mineral can scratch Test by seeing if the mineral can scratch

different objects (like human fingernail, different objects (like human fingernail, copper, penny, glass, steel file)copper, penny, glass, steel file)

Find out more…Find out more…

““Electronic” Hardness TestElectronic” Hardness Test

http://www.childrensmuseum.org/http://www.childrensmuseum.org/geomysteries/cube/b2.html geomysteries/cube/b2.html

Physical Properties of MineralsPhysical Properties of Minerals (can be used to identify the mineral)(can be used to identify the mineral)

Cleavage & FractureCleavage & Fracture The way the mineral breaks Cleavage—minerals break

along smooth, flat surfaces and every fragment has the same general shape

Fracture—minerals that break at random with rough or jagged edges

Cleavage or Fracture?Cleavage or Fracture?1.

4.

3.

2.

Physical Properties of MineralsPhysical Properties of Minerals (can be used to identify the mineral)(can be used to identify the mineral)

Other PropertiesOther Properties Specific gravity (*excellent clue to

mineral’s identity) Attraction to magnets Bending of light Reaction with hydrochloric acid Smell & taste

http://www.childrensmuseum.org/geomysteries/cube/b4.html

Watch Brainpop—“Mineral Identification”

1. If a mineral can scratch your fingernail, the mineral is _______________ than your fingernail.

2. What is luster?

Watch Classifying Minerals ClipWatch Classifying Minerals Clip

What is a gem?What is a gem? A Mineral OR Rock that has value Rare ! Sometimes polishing or cutting will

add value