igneous
Red granite
Granite; mainly quartz (SiO₂), potassium feldspar, plagioclase, and biotite/hornblende
AI-generated identification · may be incorrectCoarse-grained, pink-red and black mottled appearance; vitreous quartz and feldspar luster, interlocking crystals, no foliation, hardness about 6–7 Mohs, and specific gravity roughly 2.63–2.75.
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Physical properties
Coarse-grained, pink-red and black mottled appearance; vitreous quartz and feldspar luster, interlocking crystals, no foliation, hardness about 6–7 Mohs, and specific gravity roughly 2.63–2.75.
Formation & geological history
A plutonic 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 for countertops, monuments, building facades, paving, aggregate, and ornamental stone; small natural specimens have modest collector value.
Geological facts
The red color generally comes from iron-bearing potassium feldspar, while dark grains are usually biotite or amphibole. Its coarse texture records prolonged underground cooling.
Field identification & locations
Identify it by visible interlocking quartz, feldspar, and dark mica/amphibole grains, lack of layering, and inability to scratch it easily with a steel knife. Common worldwide, especially in continental shields and mountain belts.
