igneous
Granite
Granite
Hardness: 6-7 Mohs; Color: Grayish-white with black specks; Luster: Dull to vitreous; Crystal structure: Phaneritic (medium-to-coarse grained); Specific gravity: 2.63-2.75
- Hardness
- 6-7 Mohs
- Color
- Grayish-white with black specks
- Luster
- Dull to vitreous
Identified More igneous →
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Physical properties
Hardness: 6-7 Mohs; Color: Grayish-white with black specks; Luster: Dull to vitreous; Crystal structure: Phaneritic (medium-to-coarse grained); Specific gravity: 2.63-2.75
Formation & geological history
Formed by the slow crystallization of magma below Earth's surface. Primarily composed of quartz, feldspar, and mica. This intrusive rock can date back billions of years or be as young as a few million years depending on the pluton.
Uses & applications
Used extensively in construction for countertops, floor tiles, paving stones, curbing, monuments, and as aggregate for road base.
Geological facts
Granite is the most common igneous rock found at Earth's surface and makes up a large part of the continental crust. Half Dome in Yosemite National Park is a massive granite monolith.
Field identification & locations
Identify by its interlocking 'salt and pepper' crystalline texture and extreme hardness. Commonly found in mountainous regions or areas where ancient crust is exposed.
