igneous
Granite (Unakite / Feldspar-rich Granite)
Granite (composed of Potassium Feldspar, Quartz, and Biotite/Epidote)
Hardness: 6-7 on Mohs scale; Color: Pinkish-red, reddish-brown, green, and dark black spots; Luster: Vitreous to dull; Crystal structure: Phaneritic (medium-to-coarse interlocking crystals); Cleavage: Perfect on feldspar grains.
- Hardness
- 6-7 on Mohs scale
- Color
- Pinkish-red, reddish-brown, green, and dark black spots
- Luster
- Vitreous to dull
Identified More igneous →
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Physical properties
Hardness: 6-7 on Mohs scale; Color: Pinkish-red, reddish-brown, green, and dark black spots; Luster: Vitreous to dull; Crystal structure: Phaneritic (medium-to-coarse interlocking crystals); Cleavage: Perfect on feldspar grains.
Formation & geological history
Formed by the slow crystallization of magma deep beneath Earth's surface (plutonic environments). Over millions of years, tectonic uplift and erosion expose it at the surface.
Uses & applications
Widely used as a construction material, dimension stone, countertop material, and in gravel/aggregate form. Attractive reddish/green specimens are used as decorative stones or lapidary material.
Geological facts
Granite makes up a major portion of the Earth's continental crust. The pink-to-red color comes from abundant orthoclase potassium feldspar, while dark patches are usually biotite mica or amphibole.
Field identification & locations
Identify in the field by its interlocking coarse grains, distinct pink/red potassium feldspar, translucent quartz, and dark mafic minerals. Abundant worldwide in continental shields and mountain cores.
