What is a Mineral? Naturally-formed solid substance with a crystal structure Naturally-formed solid substance with a crystal structure Pyromorphite
What do all minerals have in common? All: 1. Are formed by natural processes. 2. Are NOT alive and NEVER were alive (inorganic) 3. Have a definite volume and shape (solid) 4. Are elements or compounds with a unique chemical makeup 5. Are made up of particles that are arranged in a pattern that is repeated over and over (called a CRYSTAL)
Watch “Crystals” by Brainpop…Crystals 1.What element are diamonds made from? 2. What do all crystals have in common?
Mineral Groups Minerals are grouped by the elements they are made of. Minerals are grouped by the elements they are made of. Amethyst Beryl (Emerald)Calcite
Mineral Groups – Silicates Silicates Silicates Tetrahedron Tetrahedron fundamental building block fundamental building block 4 oxygen ions surrounding a much smaller silicon ion 4 oxygen ions surrounding a much smaller silicon ion Silicon-oxygen tetrahedron (SiO 4 ) 4-
Mineral Groups Non-ferromagnesian Silicates (K, Na, Ca, Al) Ferromagnesian Silicates (Fe, Mg) Oxides Carbonates Sulfides/sulfates Native elements
Mineral Group CharacteristicsExamples Silicates Contain oxygen & silica Contain oxygen & silica The most abundant group of minerals The most abundant group of minerals Quartz, mica MICA Quartz
Quartz Group light silicates (pure SiO 2 ) no cleavage (conchoidal fracture) hard, resistant to weathering Quartz
Feldspar Group Non-ferromagnesian Silicates (K, Na, Ca, Al) light silicates (K, Na, Ca, Al) 2-directions of cleavage (at 90 degrees) K-feldspar Orthoclase Plagioclase Ca/Na-feldspar
Pyroxene Groups Ferromagnesian Silicates (Fe, Mg) dark silicates (Fe-Mg) 2 directions of cleavage at nearly 90° Augite
Amphibole Groups Non-ferromagnesian Silicates (K, Na, Ca, Al) Ferromagnesian Silicates (Fe, Mg) Oxides Carbonates Sulfides/sulfates Native elements dark silicates (Fe-Mg) 2 directions of cleavage not at 90° Hornblende
Mica Group & Clay Minerals Non-ferromagnesian Silicates (K, Na, Ca, Al) Ferromagnesian Silicates (Fe, Mg) Oxides Carbonates Sulfides/sulfates Native elements light silicates (K, Al) 1 direction of cleavage
Shapes of Silicates
Mineral Group CharacteristicsExamples Non-Silicates Make up only 5% of the Earth’s crust Make up only 5% of the Earth’s crust Include some of the most important minerals Include some of the most important minerals iron, copper, gold, silver, diamonds, rubies Silver Gold Ruby Iron Copper Diamond
Mineral Group CharacteristicsExamples Carbonates Carbon & oxygen and a positive ion, such as calcium Carbon & oxygen and a positive ion, such as calcium Calcite (CaCO 3 ) Calcite with Duftite inclusions
Mineral Group CharacteristicsExamples Oxides Metallic ion and oxygen Hematite (Fe 2 )O 3
Mineral Group CharacteristicsExamples Sulfides Sulfur and a metallic ion Galena (PbS)
Mineral Group CharacteristicsExamples Sulfates Metallic ion, Sulfur & oxygen Barite (BaSO 4 ) Barite on Calcite BaSo4 / CaCO3 Barite BaSo4
Mineral Group CharacteristicsExamples Native Elements Single elements Gold (Au), Diamond (C), Silver (Ag)
How do minerals form? 1) Cooling of magma (hot, liquid rock and minerals inside the earth (from the mantle)) 1) Cooling of magma (hot, liquid rock and minerals inside the earth (from the mantle)) Fast Cooling = No Crystals (mineraloids) Fast Cooling = No Crystals (mineraloids) Medium Cooling = small crystals Medium Cooling = small crystals Slow Cooling = large crystals Slow Cooling = large crystals
How do minerals form? 2) Elements dissolved in liquids (usually water) 2) Elements dissolved in liquids (usually water)
Physical Properties of Minerals (can be used to identify the mineral) Color Color Luster Luster Habit (Shape) Habit (Shape) Cleavage & Fracture Cleavage & Fracture Streak Streak Hardness Hardness Other Other
Color - Most obvious, but often misleading - Different colors may result from impurities; ie., Quartz
Luster Surface reflection Surface reflection metallic = shiny like metal metallic = shiny like metal non-metallic = dull, non-shiny surface non-metallic = dull, non-shiny surface Metallic - pyrite Non-metallic - calcite
Mineral Habit (Shape) Shape a mineral takes if grown unimpeded Amethyst Babingtonite Diamond Fluorite
Cleavage & Fracture The way the mineral breaks The way the mineral breaks Cleavage—minerals break along smooth, flat surfaces and every fragment has the same general shape 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 Fracture—minerals that break at random with rough or jagged edges
Cleavage or Fracture?
Streak The color of the powdered form of the mineral The color of the powdered form of the mineral The color of the streak can be different than the mineral The color of the streak can be different than the mineral Minerals must be softer than the streak plate Minerals must be softer than the streak plate
Streak…can help identify quartz
Hardness How easily a mineral scratches materials How easily a mineral scratches materials Mohs Hardness Scale Mohs Hardness Scale Scale from 1 (softest) to 10 (hardest) Scale from 1 (softest) to 10 (hardest) Test by seeing if the mineral can scratch different objects (like human fingernail, copper, penny, glass, steel file) Test by seeing if the mineral can scratch different objects (like human fingernail, copper, penny, glass, steel file)
Find out more… “Electronic” Hardness Test “Electronic” Hardness Test steries/cube/b2.html steries/cube/b2.html
Other Properties Specific gravity (*excellent clue to mineral’s identity) Specific gravity (*excellent clue to mineral’s identity) Attraction to magnets Attraction to magnets Bending of light Bending of light Reaction with hydrochloric acid Reaction with hydrochloric acid Smell & taste Smell & taste
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 Clip Classifying Minerals Classifying Minerals