igneous
Granite Pebble
Intrusive Igneous Rock (Granite/Diorite aggregate)
Hardness: 6-7 on Mohs scale. Color: Greyish-brown with speckled white, dark, and quartz grains. Luster: Dull to earthy (water-worn surface). Texture: Fine to medium-grained phaneritic, rounded by river or beach erosion. Specific Gravity: ~2.65-2.75.
- Hardness
- 6-7 on Mohs scale
- Color
- Greyish-brown with speckled white, dark, and quartz grains
- Luster
- Dull to earthy (water-worn surface)
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Physical properties
Hardness: 6-7 on Mohs scale. Color: Greyish-brown with speckled white, dark, and quartz grains. Luster: Dull to earthy (water-worn surface). Texture: Fine to medium-grained phaneritic, rounded by river or beach erosion. Specific Gravity: ~2.65-2.75.
Formation & geological history
Formed deep underground by the slow cooling and crystallization of felsic to intermediate magma. Later exposed by uplift and weathering, then eroded and rounded by transport in streams, rivers, or glacial action.
Uses & applications
Commonly used as construction aggregate, landscaping gravel, river rock decoration, and for educational study.
Geological facts
Smooth, rounded river pebbles like this one acquire their shape from being tumbled against other stones over thousands of years in moving water.
Field identification & locations
Can be identified by its rounded form, grainy texture, and mixture of light-colored feldspar/quartz and dark biotite or hornblende minerals. Extremely common in riverbeds, lake shores, and glacial deposits globally.
