igneous
Granite River Pebble
Granite (composed of Quartz, Feldspar, and Mica)
Hardness: 6-7 Mohs; Color: Salt and pepper/mottled gray, white, and black; Luster: Vitreous to dull; Crystal structure: Phaneritic (coarse-grained); Specific Gravity: 2.63-2.75
- Hardness
- 6-7 Mohs
- Color
- Salt and pepper/mottled gray, white, and black
- Luster
- Vitreous to dull
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Physical properties
Hardness: 6-7 Mohs; Color: Salt and pepper/mottled gray, white, and black; Luster: Vitreous to dull; Crystal structure: Phaneritic (coarse-grained); Specific Gravity: 2.63-2.75
Formation & geological history
Formed from the slow crystallization of magma below Earth's surface. This specific specimen has been tumbled and rounded by river or stream erosion, likely over hundreds to thousands of years. Granitic rocks can date back billions of years.
Uses & applications
Large-scale use in construction (curbstones, decorative gravel), landscaping, and interior design (countertops). Small river stones are used in Zen gardens and aquarium decor.
Geological facts
Granite is the most common rock found in the Earth's continental crust. It is exceptionally durable, which is why ancient Egyptian monuments and modern skyscrapers alike utilize it.
Field identification & locations
Identified by its 'salt and pepper' appearance and hardness (it cannot be scratched by a steel knife). Commonly found in riverbeds, glacial tills, and mountainous regions worldwide. Collectors look for unique mineral patterns.
