MINERALS

CONCEPT REVIEW EARTH IS MOSTLY MADE UP OF ROCK EARTH IS MOSTLY MADE UP OF ROCK ROCKS ARE MADE UP OF MINERALS ROCKS ARE MADE UP OF MINERALS THERE ARE NAMED MINERALS THERE ARE NAMED MINERALS MOST ROCKS ARE MADE OF JUST A FEW OF THESE MOST ROCKS ARE MADE OF JUST A FEW OF THESE

CONCEPT REVIEW ATOMS COMBINE NATURALLY TO FORM MINERALS ATOMS COMBINE NATURALLY TO FORM MINERALS ATOMS BOND IN DIFFERENT WAYS ATOMS BOND IN DIFFERENT WAYS COVALENT COVALENTIONICMETALLIC

HOW DO WE KNOW IT’S A MINERAL? CHARACTERISTICS OF A MINERAL… MUST: 1.Be naturally occurring 2.Be inorganic (generally) 3.Be a solid 4.Have a definite chemical composition 5.Have a repeating crystal lattice

Naturally Occurring Mineral must be found in nature Mineral must be found in nature Not artificially created in the laboratory Not artificially created in the laboratory For example – cubic zirconium is NOT a mineral since it is artificial only However, halite created in the lab IS a mineral because it is also found in nature

Inorganic Mineral can not be formed from living Mineral can not be formed from livingthings Inorganic substances are non-living Inorganic substances are non-living (past, present, future) Exception – calcite is produced by living sea creatures Inorganic substances do not contain chains of carbon atoms (are not carbon based) Inorganic substances do not contain chains of carbon atoms (are not carbon based) Exceptions are Graphite (C) and Diamond (C)

Solid Minerals cannot be liquids or gases Minerals cannot be liquids or gases For example – water is NOT a mineral, but glacial ice IS a mineralFor example – water is NOT a mineral, but glacial ice IS a mineral

Definite Crystal Structure Highly ordered atomic arrangement of atoms in regular geometric patterns Highly ordered atomic arrangement of atoms in regular geometric patterns 8 ApatiteFeldsparDiamondQuartz

Minerals are crystalline substances which means that their atoms or ions are arranged in an orderly and repetitive manner. The gemstone opal is not a mineral even though it contains the same elements as quartz. Opal does not have an orderly internal structure.

Repeating Crystal Lattice Minerals with the same chemical composition can have different lattices – making them different minerals! Minerals with the same chemical composition can have different lattices – making them different minerals! For example – take a look at these lattices for Diamond (C) and Graphite (C).

Definite Chemical Formula Minerals are expressed by a specific chemical formula Minerals are expressed by a specific chemical formula - Gold (Au) -Calcite (CaCO 3 ) -Quartz (SiO 2 ) -Pyrite (FeS 2 ) -Halite (NaCl) -Halite (NaCl)

HOW DO MINERALS FORM? 1. CRYSTALLIZATION OF MAGMA 2. PRECIPITATION 3. METAMORPHISM - CHANGES IN TEMPERATURE AND PRESSURE 4. CHEMICAL WEATHERING 5. FROM HYDROTHERMAL SOLUTIONS

Cooling of Magma Magma is a molten “soup” of minerals Magma is a molten “soup” of minerals As it cools, certain minerals crystallize at different temperatures This removes some elements from the magma and changes its composition

Precipitation Precipitation here refers to the formation of a solid from a liquid Precipitation here refers to the formation of a solid from a liquid Can be as simple as evaporation or a chemical reaction where two liquids combine to form a solidCan be as simple as evaporation or a chemical reaction where two liquids combine to form a solid Calcite, gypsum, and halite form this way.Calcite, gypsum, and halite form this way.

Metamorphism is a change in a mineral (or rock) brought about by changes in heat and pressure. Metamorphism is a change in a mineral (or rock) brought about by changes in heat and pressure. Increased heat and/or pressure causes mineral structure (lattices) to change – resulting in a new mineralIncreased heat and/or pressure causes mineral structure (lattices) to change – resulting in a new mineral Minerals can be recrystallized or foliated (aligned in layers)Minerals can be recrystallized or foliated (aligned in layers)Metamorphism

Chemical Weathering Chemical weathering of minerals occurs at the surface of the earth in soils and clays Chemical weathering of minerals occurs at the surface of the earth in soils and clays Chemical reactions take place and change the mineral structures – resulting in a new mineral Chemical reactions take place and change the mineral structures – resulting in a new mineral For example – orthoclase reacts with acid rain to form kaolinite For example – orthoclase reacts with acid rain to form kaolinite

Hydrothermal Solutions A hydrothermal solution is a hot water solution containing a variety of substances A hydrothermal solution is a hot water solution containing a variety of substances The temperature of the water allows a great deal of mixing and reacting to take place The temperature of the water allows a great deal of mixing and reacting to take place Results in numerous Results in numerous combinations of substances – forming many minerals Sulfides are often Sulfides are often formed this way

Summary A mineral is a naturally occurring solid with a definite chemical formula and crystal lattice and is generally inorganic. A mineral is a naturally occurring solid with a definite chemical formula and crystal lattice and is generally inorganic. Minerals can form in five common ways – magma cooling, precipitation, metamorphism, chemical weathering, and hydrothermal solutions. Minerals can form in five common ways – magma cooling, precipitation, metamorphism, chemical weathering, and hydrothermal solutions.