igneous
Granite
Coarse-grained granitoid, mainly quartz, potassium feldspar, plagioclase, and biotite/hornblende
AI-generated identification · may be incorrectHardness about 6–7 Mohs; pink, gray, white, and black interlocking grains with a speckled, vitreous-to-dull luster. Massive, nonfoliated texture and no prominent cleavage as a whole; specific gravity about 2.6–2.7.
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Physical properties
Hardness about 6–7 Mohs; pink, gray, white, and black interlocking grains with a speckled, vitreous-to-dull luster. Massive, nonfoliated texture and no prominent cleavage as a whole; specific gravity about 2.6–2.7.
Formation & geological history
Intrusive igneous rock formed by slow crystallization of silica-rich magma deep in the continental crust, commonly during Precambrian to Phanerozoic mountain-building events.
Uses & applications
Widely used for countertops, monuments, building stone, paving, and aggregate; attractive polished pieces are collected as decorative specimens.
Geological facts
The pink color commonly comes from potassium feldspar, while dark grains are biotite or amphibole; weathering rounds granite into cobbles and boulders.
Field identification & locations
Identify it by visible, interlocking quartz and feldspar crystals rather than layers or aligned foliation. Common worldwide, especially in continental shields and mountain belts; this specimen may also be a related granite pegmatite or granodiorite.
