 Minerals form in a variety of environments in Earth’s crust.  Each of these environments has a different set of physical and chemical conditions.  The environment in which a mineral forms determines the mineral’s properties.  Environments in which minerals form may be on or near Earth’s surface or deep beneath Earth’s surface.

 In general, minerals form through crystallization of materials.

 Crystallization is the process by which atoms are arranged to form a material with a crystal shape.

 The size of these crystals depends on several factors: t he rate at which magma cools, the amount of gas magma contains, and the chemical composition of magma all affect crystal size.

 Minerals can form as hot magma cools deep inside the crust, or as lava hardens on the surface.  When these liquids cool to the solid state, they form mineral crystals.  Minerals can form as hot magma cools deep inside the crust, or as lava hardens on the surface.  When these liquids cool to the solid state, they form mineral crystals.

Metamorphic Rocks  Where minerals form when rocks are altered by changes in pressure, temperature, or chemical make-up.  (calcite, garnet, graphite, hematite, magnetite, mica, and talc)

Pegmatite  Teardrop-shaped bodies with large crystals, such as gemstones, that form when magma moves upward. form during the final stage of a magma’s crystallization. They are extreme because they contain exceptionally large crystal (many gemstones, such as topaz, tourmaline)

Plutons  Magma body that moves upward and cools before it reaches the surface, forming crystals;. (mica, feldspar, magnetite, quartz) a body of intrusive igneous rock (called a plutonic rock) that is crystallized from magma slowly cooling below the surface of the Earth

Evaporating Salt Water  When a body of salt water dries up, minerals such as gypsum and halite are left behind. These minerals crystalize.

Limestone  Rocks formed when surface water and ground water carry dissolved materials to lakes and seas where they crystallize on the bottom (calcite, dolomite)

Hot-Water Solutions  Environment in which groundwater works its way downward and is heated by magma and then reacts with minerals. (gold, copper, sulfur, pyrite, galena)

Type of Material Main feature Common Objects Made From It Metal has shiny surfaces does not transmit light transmits heat and electricity easily can be rolled into sheets or stretched into wires Can be processed into metals, they are strong and do not rust Used in aircrafts, automobiles, computers, communications and electronic equipment, and spacecraft Examples: gold, silver, and copper Nonmetal dull surfaces, may be describe as vitreous, glassy, pearly, greasy, or silky may let light pass through them, and are good insulators of electricity Some of the most widely used minerals in industry Calcite – major component of concrete used in roads, buildings, bridges, and other structures Industrial sand and gravel, or silica, are used in glassmaking and computer chips

 Mining: is extracting (removal) ore or minerals from the ground  Ore: rocks that have concentration of valuable minerals to be mined for profit.

 There are two main types of mines. 1)Surface Mining 2)Subsurface Mining

 Surface mining is used to remove mineral deposits on or near the Earth’s surface.  There are 3 types of surface mines: 1. Open-pit: removes large, near surface deposits of minerals such as gold and copper creating a big pit. The pit grows larger as more ore is removed 2. Quarries: type of open-pit mining that produces rocks and mineral used to make buildings: stone, crushed rock, sand, gravel 3. Strip Mining: Similar to open pit, but removes the ore in large strips instead of from a pit

 This quarry in northwest Georgia is an open pit used to mine granite.

Open Pit Mining  Dig hole and remove ores

Area Strip Mining Cut new strips away; spoil placed on side, mineral taken out. Types of Surface Mining

 Collapse/subsidence of land from subsurface mines.  Causes houses to tilt, sewer lines crack, gas mains break.  Collapse/subsidence of land from subsurface mines.  Causes houses to tilt, sewer lines crack, gas mains break.

 Wind/water carry away [by erosion] toxic mining waste.  Goes in food webs and watersheds.

 Transportation of minerals  global warming, lung probs.

Mine reclamation is the process by which land used for mining is returned to its original state or better. Has been required by law since the mid-1970’s.

 To reduce the effects of mining, reduce our need for minerals, reuse, and recycle. Reduce: use less Reuse: get as much use out of the materials you have. Recycle: use the material to make something else, rather than throwing it away.