igneous
Granite River Pebble
Granite (Felsic Plutonic Rock)
Hardness: 6-7 Mohs; Color: Salt and pepper (white/gray quartz, cream feldspar, black mica); Luster: Vitreous to dull; Crystal structure: Phaneritic (coarse-grained); Specific gravity: 2.63 - 2.75
- Hardness
- 6-7 Mohs
- Luster
- Vitreous to dull
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Physical properties
Hardness: 6-7 Mohs; Color: Salt and pepper (white/gray quartz, cream feldspar, black mica); 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 specimen has been rounded and smoothed through fluvial erosion in a riverbed or stream environment.
Uses & applications
Used extensively in construction for countertops, floor tiles, and gravel. Polished river stones are popular in landscaping, aquariums, and home decor.
Geological facts
Granite is one of the hardest and most durable common rocks, making a significant portion of the Earth's continental crust. Over 300 million years old in many regional deposits.
Field identification & locations
Identify by its visible interlocking crystals of different colors. It cannot be easily scratched by a steel blade. Commonly found in riverbeds, glacial moraines, and mountainous regions worldwide.
