igneous
Granite Pebble (River Rock)
Granite
Hardness: 6-7 on Mohs scale. Color: Speckled tan, cream, brown, and grey. Luster: Dull to sub-vitreous. Texture: Phaneritic (medium-grained), smooth rounded egg shape due to hydraulic erosion.
- Hardness
- 6-7 on Mohs scale
- Color
- Speckled tan, cream, brown, and grey
- Luster
- Dull to sub-vitreous
Identified More igneous →
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Physical properties
Hardness: 6-7 on Mohs scale. Color: Speckled tan, cream, brown, and grey. Luster: Dull to sub-vitreous. Texture: Phaneritic (medium-grained), smooth rounded egg shape due to hydraulic erosion.
Formation & geological history
Formed from the slow crystallization of felsic magma deep beneath the Earth's surface (plutonic igneous rock). The egg-like shape was formed through long-term river or beach erosion (abrasion by water and gravel).
Uses & applications
Used primarily as decorative river rock, landscaping, educational geological specimens, or massage stones.
Geological facts
Smooth egg-shaped rocks like this are naturally shaped over hundreds or thousands of years in riverbeds or coastal wave zones where tumbling action smooths out all angular edges.
Field identification & locations
Look for the classic salt-and-pepper or mottled quartz and feldspar interlocking crystal texture combined with an unusually smooth, oval/egg-shaped profile created by water action.
