igneous
Granite Water-Worn Pebble
Intermediate to Felsic Plutonic Rock (Granite)
Hardness: 6.0-7.0 (Mohs scale), Color: Mottled gray, black, and white, Luster: Dull (weathered/rounded), Texture: Phaneritic (visible crystals), Specific Gravity: ~2.6-2.7
- Hardness
- 6
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Physical properties
Hardness: 6.0-7.0 (Mohs scale), Color: Mottled gray, black, and white, Luster: Dull (weathered/rounded), Texture: Phaneritic (visible crystals), Specific Gravity: ~2.6-2.7
Formation & geological history
Formed from the slow cooling of silica-rich magma deep within the Earth's crust (plutonic). This specific specimen has been rounded by fluvial (river) or coastal (beach) erosion over a long period.
Uses & applications
Primarily used as decorative landscaping stones, aquarium gravel, or as a fundamental building material in crushed form for road construction and concrete.
Geological facts
Granite is one of the most common rocks in the Earth's continental crust. It contains significant amounts of quartz and feldspar, which make it extremely resistant to weathering compared to other rock types.
Field identification & locations
Identify by its salt-and-pepper appearance and the presence of visible mica, quartz, and feldspar grains. These rounded pebbles are ubiquitous in riverbeds and on rocky shorelines worldwide.
