igneous
Granite Pebble
Granite (Phaneritic Igneous Rock)
Hardness: 6-7 Mohs; Color: Mottled pink, grey, and black; Luster: Vitreous to dull; Crystal structure: Phaneritic (coarse-grained); Cleavage: Distinct in feldspar grains; Specific gravity: 2.63 to 2.75
- Hardness
- 6-7 Mohs
- Color
- Mottled pink, grey, and black
- Luster
- Vitreous to dull
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Physical properties
Hardness: 6-7 Mohs; Color: Mottled pink, grey, and black; Luster: Vitreous to dull; Crystal structure: Phaneritic (coarse-grained); Cleavage: Distinct in feldspar grains; Specific gravity: 2.63 to 2.75
Formation & geological history
Formed from the slow cooling of silica-rich magma deep underground (plutonic). This specific specimen appears to be a water-worn or rounded pebble from a riverbed or glacial deposit.
Uses & applications
Commonly used in large scale for construction, countertops, and monuments. Small pebbles are used for landscaping, aquarium gravel, or decorative garden features.
Geological facts
Granite is the most common rock found in the Earth's continental crust. The pink color in this specimen is caused by potassium feldspar (orthoclase).
Field identification & locations
Identify by the 'salt and pepper' appearance of interlocking crystals. Look for small shiny flakes of mica and glassy grey quartz alongside pinkish feldspar. Commonly found in mountainous regions or glacial drift.
