igneous
Granite
Phaneritic Felsic Igneous Rock
Hardness: 6-7 Mohs; Color: Mottled pink/orange, grey, and black; Luster: Dull to sub-vitreous; Crystal structure: Phaneritic (coarse-grained); Specific Gravity: 2.63-2.75
- Hardness
- 6-7 Mohs
- Color
- Mottled pink/orange, grey, and black
- Luster
- Dull to sub-vitreous
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Physical properties
Hardness: 6-7 Mohs; Color: Mottled pink/orange, grey, and black; Luster: Dull to sub-vitreous; Crystal structure: Phaneritic (coarse-grained); Specific Gravity: 2.63-2.75
Formation & geological history
Formed from the slow cooling and crystallization of magma deep beneath the Earth's surface (plutonic). This specimen shows weathering characteristic of a river rock or glacial transport.
Uses & applications
Used extensively in construction, countertops, monuments, and as crushed stone for road base.
Geological facts
Granite makes up a large portion of the Earth's continental crust. The pink/orange color in this specimen comes from Potassium Feldspar (orthoclase).
Field identification & locations
Identify by its 'salt and pepper' or mottled appearance with visible interlocking crystals of quartz, feldspar, and mica. This rounded specimen is likely a cobble found in a fluvial or glacial deposit.
