Minerals Notes PDF

MINERALS  Mineral Characteristics Mineral is a naturally occurring, inorganic solid, with a specific chemical composition and a definite crystalline structure. Fact #1 Fact #2 Fact #3 Minerals are ALL minerals are M...

MINERALS  Mineral Characteristics Mineral is a naturally occurring, inorganic solid, with a specific chemical composition and a definite crystalline structure. Fact #1 Fact #2 Fact #3 Minerals are ALL minerals are Minerals are solids naturally occurring inorganic Crystal is a solid in which atoms are Fact #4 Fact #5 arranged in Most minerals are Have a definite repeating made from crystal structure patterns compounds  EXAMPLES OF MINERALS Olivine Augite Hornblende Biotite calcium-rich plagioclase (anorthite) sodium-rich plagioclase (albite) potassium-rich feldspar (commonly orthoclase) Muscovite Quartz Calcite HOW MINERALS ARE FORMED Solutions Magma Minerals that form from the Molten material that forms evaporation of the liquid in and accumulates below which they were dissolved Earth’s surface is called are called evaporites. magma. Small crystals form from rapidly cooling magma, and large crystals form from slowly cooling magma. IDENTIFYING MINERALS Color Luster most noticeable The way that a mineral characteristic, but is reflects light from its also one of the least surface is called reliable clues luster. Streak Cleavage/fracture Streak is the color of a A mineral that breaks easily and mineral when it is evenly along weak atomic bonds is broken up and said to have cleavage. powdered. Minerals that break with rough or jagged edges because of tightly bonded atoms are said to fracture. IDENTIFYING MINERALS Crystal Hardness Shape Hardness is a Some minerals form measure of how easily such distinct crystal a mineral can be shapes that they are scratched immediately recognizable. Special Properties Several special properties of minerals can also be used for identification including magnetism, iridescence, double refraction, and fluorescence. ROCK FORMING MINERALS Rock-forming minerals are primarily composed of the eight most common elements in Earth’s crust (Shown in graph to the right) Quartz, Feldspar, Amphibole, Olivine, Mica, Pyroxene, Garnet and Calcite are the most common rock forming minerals Eight to ten of these minerals make up most of the rocks in Earth’s crust. TYPES OF MINERALS Types of Minerals Silicates Minerals that contain silicon and oxygen, and usually one or more other elements, are known as silicates. Silicates make up approximately 96%of the minerals present in Earth’s crust. Carbonates Carbonates are minerals composed of metallic elements and the carbonate ion CO32– Magma is less dense than the surrounding solid rock, so it can rise upward into the cooler layers of Earth’s interior, where it cools and crystallizes. Types of Minerals Oxides Oxides are compounds of oxygen and a metal, such as hematite (Fe2O3) Sulfides Sulfides are compounds of sulfur and one or more elements, such as pyrite (FeS2). Sulfates Sulfates are compounds of elements with the sulfate ion (SO42–), such as anhydrite (CaSO4) Types of Minerals Halides Halides are made up of chloride or fluoride along with calcium, sodium, or potassium, such as halite (NaCl). Native Elements Native elements are made up of one element ONLY, such as silver (Ag). Economic Minerals Minerals are used to make computers, cars, televisions, desks, roads, etc. Ore A mineral is an ore if it contains a useful substance that can be mined at a profit. The classification of a mineral as an ore can change if the supply of or demand for that mineral changes. Gems Gems are valuable minerals that are prized for their rarity and beauty.