igneous
Polished orbicular granite (likely gabbroic granite)
Granite, chiefly quartz (SiO₂), feldspar, and biotite/amphibole; exact variety uncertain from the photograph
AI-generated identification · may be incorrectCoarse-grained, black-and-tan mottled rock with a polished, low-to-waxy luster; individual grains are interlocking and lack cleavage as a whole. Typical hardness is about 6–7 Mohs and specific gravity roughly 2.6–2.9.
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Physical properties
Coarse-grained, black-and-tan mottled rock with a polished, low-to-waxy luster; individual grains are interlocking and lack cleavage as a whole. Typical hardness is about 6–7 Mohs and specific gravity roughly 2.6–2.9.
Formation & geological history
An intrusive igneous rock that crystallized slowly from magma deep underground, probably during Precambrian to Phanerozoic crustal formation; the rounded shape is human-polished.
Uses & applications
Used for decorative stone, paperweights, palm stones, cabochons, and small carvings; comparable slabs may be used for countertops and monuments.
Geological facts
The dark minerals are likely biotite, hornblende, or pyroxene, while tan areas are feldspar; visible quartz appears limited, so it may technically be a diorite or gabbro rather than granite.
Field identification & locations
Identify it by its coarse interlocking crystals, strong black-and-pink/tan contrast, and resistance to scratching glass. Common source regions include India, Brazil, Scandinavia, and North America; a thin section or mineral test is needed for precise naming.
