igneous
Granite
Coarse-grained felsic intrusive igneous rock, chiefly quartz, K-feldspar, plagioclase, and mica (commonly biotite).
AI-generated identification · may be incorrectTypically light gray to pink, speckled black and white, with a granular crystalline texture and glassy quartz luster; hardness about 6–7 Mohs, no cleavage as a rock, and specific gravity roughly 2.6–2.7.
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Physical properties
Typically light gray to pink, speckled black and white, with a granular crystalline texture and glassy quartz luster; hardness about 6–7 Mohs, no cleavage as a rock, and specific gravity roughly 2.6–2.7.
Formation & geological history
Formed by slow crystallization of silica-rich magma deep in the continental crust, generally during Precambrian to recent geological periods. The specimen’s exact age cannot be determined from the image.
Uses & applications
Widely used for countertops, monuments, building stone, paving, and aggregate; attractive polished pieces are collected but usually have modest value.
Geological facts
Large visible crystals indicate intrusive cooling rather than volcanic eruption. Pink grains are potassium feldspar, translucent gray grains are quartz, and dark flakes are commonly biotite mica.
Field identification & locations
Identify it by its coarse interlocking grains and absence of layers or vesicles; unlike basalt, it is generally pale and quartz-rich. Common worldwide, especially in continental mountain belts.
