igneous
Granite Pebble
Phaneritic Felsic Igneous Rock
Hardness: 6-7 Mohs; Color: Mottled gray, white, and black; Luster: Dull to vitreous; Crystal structure: Phaneritic (coarse-grained); Cleavage: Indistinct; Specific Gravity: 2.63-2.75
- Hardness
- 6-7 Mohs
- Color
- Mottled gray, white, and black
- Luster
- Dull to vitreous
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Physical properties
Hardness: 6-7 Mohs; Color: Mottled gray, white, and black; Luster: Dull to vitreous; Crystal structure: Phaneritic (coarse-grained); Cleavage: Indistinct; Specific Gravity: 2.63-2.75
Formation & geological history
Formed from the slow cooling of silica-rich magma deep underground. This specific specimen has been shaped by water erosion (weathering) into a river pebble.
Uses & applications
Used in construction, gravel, landscaping, and as a common decorative garden stone.
Geological facts
Granite is the most common rock in Earth's continental crust. Over millions of years, larger formations break down and are transported by water, resulting in rounded pebbles like this one.
Field identification & locations
Identify by its 'salt and pepper' appearance and hardness (it will scratch glass). Commonly found in riverbeds, glacial tills, and mountainous areas where erosion has exposed the continental basement.
