igneous
Granite Pebble
Granitoid (Quartz-Feldspar dominant rock)
Hardness: 6-7 on Mohs scale; Color: Mottled white, pink, tan, and black; Luster: Vitreous to dull; Crystal structure: Phaneritic (coarse-grained); Specific gravity: approx. 2.65-2.75
- Hardness
- 6-7 on Mohs scale
- Color
- Mottled white, pink, tan, and black
- Luster
- Vitreous to dull
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Physical properties
Hardness: 6-7 on Mohs scale; Color: Mottled white, pink, tan, and black; Luster: Vitreous to dull; Crystal structure: Phaneritic (coarse-grained); Specific gravity: approx. 2.65-2.75
Formation & geological history
Formed through the slow cooling and crystallization of magma beneath the Earth's surface (plutonic). This specific specimen shows signs of water-worn erosion, likely from a river or beach environment.
Uses & applications
Polished stones like this are used in aquarium decor, landscaping, gravel, and as worry stones. Large-scale granite is used in construction and countertops.
Geological facts
Granite is the primary component of the Earth's continental crust. The different colors come from specific minerals: white/tan is feldspar, clear/grey is quartz, and black is typically biotite mica or hornblende.
Field identification & locations
Identify by its 'salt and pepper' appearance and visible interlocking crystals. Common in glacial till, riverbeds, and mountain ranges. It will not react with acid, unlike limestone.
