igneous
Granite
Granite, a coarse-grained intrusive felsic igneous rock composed chiefly of quartz and feldspar
AI-generated identification · may be incorrectLight gray, speckled with dark minerals; interlocking visible crystals and no layering. Typical hardness is about 6–7 Mohs; luster is mostly dull to glassy, and cleavage is expressed by its component minerals rather than the rock as a whole.
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Physical properties
Light gray, speckled with dark minerals; interlocking visible crystals and no layering. Typical hardness is about 6–7 Mohs; luster is mostly dull to glassy, and cleavage is expressed by its component minerals rather than the rock as a whole.
Formation & geological history
Magma cooled slowly deep in Earth’s crust, allowing large crystals to grow. Granite forms across many geological ages in continental crust and mountain-building regions.
Uses & applications
Used as dimension stone, countertops, paving, monuments, and aggregate; attractive hand specimens are collected.
Geological facts
The specimen’s pale groundmass and scattered dark grains are consistent with granite, though a photo cannot confirm its mineral proportions.
Field identification & locations
Look for interlocking quartz and feldspar crystals with dark biotite or amphibole, and a lack of foliation. Granite occurs worldwide; value is usually about $1–$10 for a small common specimen, depending on appearance and provenance.
