igneous
Granite Pebble
Granite (Phaneritic Igneous Rock)
Hardness: 6-7 (Mohs scale); Color: White/Light grey matrix with black speckles; Luster: Dull to vitreous; Crystal structure: Phaneritic (visible crystals); Cleavage: None (subconchoidal fracture); Specific gravity: 2.63-2.75
- Hardness
- 6-7 (Mohs scale)
- Color
- White/Light grey matrix with black speckles
- Luster
- Dull to vitreous
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Physical properties
Hardness: 6-7 (Mohs scale); Color: White/Light grey matrix with black speckles; Luster: Dull to vitreous; Crystal structure: Phaneritic (visible crystals); Cleavage: None (subconchoidal fracture); Specific gravity: 2.63-2.75
Formation & geological history
Formed from the slow cooling of silica-rich magma deep beneath the Earth's surface (plutonic formation). This specimen shows rounded edges indicating high-energy water erosion, likely a river or beach pebble.
Uses & applications
Used primarily as decorative landscaping stones, aquarium gravel, or as an educational geological sample. In bulk, crushed granite is used for road base and construction.
Geological facts
Granite is the primary rock that makes up the Earth's continental crust. Specimens like this often contain Quartz (white), Feldspar (cream), and Biotite or Hornblende (black flecks).
Field identification & locations
Identify by its 'salt and pepper' appearance and hardness (it will scratch glass). Commonly found in riverbeds, glacial tills, and coastal beaches globally. Collectors look for unique wear patterns or mineral inclusions.
