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| the study of Earth and its processes |
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| the study of materials which are extracted from the Earth for our own use and in industry |
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| more than one-tenth of the Earth's volume, is mostly iron |
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| over eight-tenths of the Earth's volume, is made up on crystalline, iron-rich rock |
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an extremely thin layer, made up of solid granite and other rocks
where we extract various economical chemicals and minerals from |
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| rocks that have solidified from magma, or molten rock |
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| rocks that are formed when the magma erupts through the upper layers and crystallizes by rapid cooling at the surface of the Earth; the rapid cooling results in small, fine-grained crystals or the glassy texture of obsidian (natural volcanic glass) |
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| rocks that are formed when magma cools more slowly below the surface of the Earth; the slow cooling allows larger crystals to form |
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| a mineral occurrence formed by precipitation from hot watery solution; typically filling cracks and cavities in rocks |
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| rocks and minerals that have had their physical structures modified or altered by the action of heat and/or pressure |
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| recrystallizing action without any melting |
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| Contact or Thermal Metamorphism |
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| metamorphism that happens as a result of temperature rises in the surrounding area when magma invades a host rock |
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| metamorphism that occurs when rocks are squeezed together |
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| Sedimentary Rock and Mineral Deposits |
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| result from the breaking down of previously formed rock by chemical and mechanical weathering, which is then transported, deposited and compacted to form further rocks and mineral deposits |
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| breaks down rocks by mechanical or chemical action |
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| acts to remove materials from rocks by transporting the fragmets away from their place of origin |
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| sedimentary deposit of sand and gravel which contains economic minerals, such as gem minerals and precious metals, concetrated by geological processes |
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sedimentary rock deposit formed by the action of water eroding and transporting rock material
'placer' deposits or 'gem gravels' are mined from certain alluvial deposits which are, or once were, river beds or lake beds |
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| describes the conditions under which the gem is formed |
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describes the geological conditions in which the gem is bound
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| the area or district in which the deposit is located |
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coarse-grained igneous rock commonly composed of quartz and feldspar
may contain large crystals of rarer minerals and are a valuable source of gemstones |
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