igneous
Granite
Phaneritic Felsic Igneous Rock
Hardness: 6-7 Mohs; Color: Salt and pepper (gray, white, black); Luster: Vitreous to dull; Crystal structure: Phaneritic (coarse-grained, visible crystals); Specific gravity: 2.63 to 2.75
- Hardness
- 6-7 Mohs
- Color
- Salt and pepper (gray, white, black)
- Luster
- Vitreous to dull
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Physical properties
Hardness: 6-7 Mohs; Color: Salt and pepper (gray, white, black); Luster: Vitreous to dull; Crystal structure: Phaneritic (coarse-grained, visible crystals); Specific gravity: 2.63 to 2.75
Formation & geological history
Formed from the slow cooling of silica-rich magma deep underground (plutonic). Typically associated with continental crust and mountain-building events over millions of years.
Uses & applications
Widely used in construction, countertops, flooring, monuments, and as crushed stone for road base and railroad ballast.
Geological facts
Granite makes up a large portion of the Earth's continental crust. It is extremely durable and resistant to acid rain, which is why it is preferred for outdoor monuments and tombstones.
Field identification & locations
Identify by its interlocking crystals of quartz, feldspar, and mica. It is common in mountain ranges and continental shields. Look for a speckled appearance and high hardness (will scratch glass).
