igneous
Granite boulder
Granite, a coarse-grained felsic intrusive igneous rock composed mainly of quartz, feldspar, and mica
AI-generated identification · may be incorrectHardness about 6–7 Mohs; speckled white-gray rock with black and pale minerals, a granular texture, and a nonmetallic luster. Interlocking crystals are visible; cleavage belongs to individual minerals rather than the rock as a whole.
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Physical properties
Hardness about 6–7 Mohs; speckled white-gray rock with black and pale minerals, a granular texture, and a nonmetallic luster. Interlocking crystals are visible; cleavage belongs to individual minerals rather than the rock as a whole.
Formation & geological history
Formed as silica-rich magma cooled slowly underground, allowing large crystals to grow. Its exact geological age cannot be determined from the image; granite ranges from Archean to recent geological periods.
Uses & applications
Used for building stone, paving, countertops, monuments, and landscaping; this rounded boulder is suitable for garden or decorative use.
Geological facts
Granite’s visible grains are typically quartz, feldspar, and dark mica or amphibole. The rounded shape likely results from weathering and abrasion, rather than the rock forming as a naturally rounded mass.
Field identification & locations
Identify it by its coarse, interlocking, light-colored grains with scattered dark minerals; it is common in continental crust and glacial or river deposits. A field check: quartz resists scratching by a steel knife, while feldspar may show cleavage surfaces.
