igneous
Pink-and-black granite fragment
Granite, primarily quartz, alkali feldspar, plagioclase, and biotite/hornblende
AI-generated identification · may be incorrectCoarse-grained, speckled pink, gray, black, and white; vitreous quartz and feldspar luster with interlocking crystals. Hardness is about 6–7 Mohs, no cleavage as a rock, and specific gravity is roughly 2.6–2.7.
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Physical properties
Coarse-grained, speckled pink, gray, black, and white; vitreous quartz and feldspar luster with interlocking crystals. Hardness is about 6–7 Mohs, no cleavage as a rock, and specific gravity is roughly 2.6–2.7.
Formation & geological history
An intrusive igneous rock formed by slow cooling and crystallization of silica-rich magma deep in the crust, commonly during Precambrian to Phanerozoic mountain-building events.
Uses & applications
Widely used as dimension stone, countertops, monuments, paving, aggregate, and decorative landscaping stone; small natural fragments have modest collecting value.
Geological facts
The pink color generally comes from potassium feldspar, while black grains are usually biotite or hornblende. Its visible interlocking crystals distinguish it from volcanic rhyolite.
Field identification & locations
Common worldwide, especially in continental crust and mountain ranges; notable sources include India, Brazil, Canada, Scandinavia, and the United States. Identify it by its coarse, randomly interlocking quartz-feldspar-mica texture; a photo cannot confirm the exact variety.
