igneous
Coarse-grained granite
Granite, chiefly quartz, feldspar, and dark mica (biotite)
AI-generated identification · may be incorrectVisible interlocking grains with a mottled cream, tan, and black appearance; quartz is Mohs 7, feldspar about 6, and biotite 2.5–3. Granite has no regular cleavage as a rock and typically has a granular texture.
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Physical properties
Visible interlocking grains with a mottled cream, tan, and black appearance; quartz is Mohs 7, feldspar about 6, and biotite 2.5–3. Granite has no regular cleavage as a rock and typically has a granular texture.
Formation & geological history
Formed as silica-rich magma cooled slowly underground, allowing large crystals to grow. Granites occur in ancient continental crust, with ages ranging from hundreds of millions to billions of years.
Uses & applications
Used as building and dimension stone, countertops, paving, and decorative aggregate; this small rough piece is mainly a collector specimen.
Geological facts
Its contrasting light and dark minerals are characteristic of granite, though a photo alone cannot confirm the precise rock type.
Field identification & locations
Look for interlocking visible crystals: glassy gray quartz, pale feldspar, and dark mica. Granite is common in continental mountain belts and exposed ancient shields.
