igneous
Granite (likely biotite granite or granodiorite)
Coarse-grained granitoid composed mainly of quartz, feldspar, and dark biotite/hornblende
AI-generated identification · may be incorrectHardness about 6–7 Mohs; mottled gray, white, and black with a granular texture and dull-to-glassy luster. Interlocking crystals and lack of layering or cleavage are typical; density is roughly 2.6–2.8 g/cm³.
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Physical properties
Hardness about 6–7 Mohs; mottled gray, white, and black with a granular texture and dull-to-glassy luster. Interlocking crystals and lack of layering or cleavage are typical; density is roughly 2.6–2.8 g/cm³.
Formation & geological history
An intrusive igneous rock crystallized slowly from silica-rich magma deep in the continental crust, commonly during Precambrian to Phanerozoic mountain-building events. Its rounded shape is probably from weathering, transport, or deliberate tumbling.
Uses & applications
Widely used as dimension stone, countertops, monuments, aggregate, and landscaping rock; this specimen has little jewelry value but is suitable for educational or decorative collecting.
Geological facts
The pale minerals are feldspar and quartz, while the dark grains are likely biotite or hornblende. Exact identification would require a fresh surface, hand lens, and ideally thin-section or chemical analysis.
Field identification & locations
Identify it by its visible interlocking crystals, gray-black-and-white pattern, high hardness, and lack of sedimentary layers or foliation; common worldwide, especially in continental shields and mountain belts.
