igneous
Granite
Intrusive Igneous Rock (Felsic)
Hardness: 6-7 Mohs; Color: Salt-and-pepper (white, grey, black); Luster: Vitreous to dull; Crystal structure: Phaneritic (coarse-grained); Specific gravity: 2.63 to 2.75
- Hardness
- 6-7 Mohs
- Color
- Salt-and-pepper (white, grey, black)
- Luster
- Vitreous to dull
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Physical properties
Hardness: 6-7 Mohs; Color: Salt-and-pepper (white, grey, black); Luster: Vitreous to dull; Crystal structure: Phaneritic (coarse-grained); Specific gravity: 2.63 to 2.75
Formation & geological history
Formed from the slow crystallization of magma below Earth's surface. This intrusive process allows large crystals of quartz, feldspar, and mica to grow over millions of years inside the crust.
Uses & applications
Widely used in construction for countertops, floor tiles, paving stones, and monuments due to its durability and aesthetic appeal. Also used as crushed stone in roadbeds.
Geological facts
Granite makes up a large part of the continental crust. The word comes from the Latin 'granum', meaning a grain. It is one of the hardest substances in the world, second only to diamonds and some other minerals.
Field identification & locations
Identified by its visible interlocking crystals of light minerals (quartz/feldspar) and dark minerals (biotite/hornblende). Common in mountain ranges and glacial deposits. Collector interest is usually for unique mineral inclusions.
