igneous
Granite Pebble
Granite
Hardness: 6-7 on Mohs scale. Color: Mottled pink, reddish-orange, grey, and white. Luster: Dull to vitreous depending on wetness/polish. Structure: Phaneritic (medium-grained interlocking crystals). Cleavage: None for the rock aggregate, though feldspars display cleavage faces. Specific Gravity: ~2.65 - 2.75.
- Hardness
- 6-7 on Mohs scale
- Color
- Mottled pink, reddish-orange, grey, and white
- Luster
- Dull to vitreous depending on wetness/polish
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Physical properties
Hardness: 6-7 on Mohs scale. Color: Mottled pink, reddish-orange, grey, and white. Luster: Dull to vitreous depending on wetness/polish. Structure: Phaneritic (medium-grained interlocking crystals). Cleavage: None for the rock aggregate, though feldspars display cleavage faces. Specific Gravity: ~2.65 - 2.75.
Formation & geological history
Formed through the slow cooling and crystallization of felsic magma deep within the Earth's crust (intrusive igneous). This particular smooth, rounded pebble shape is the result of water erosion in a river, lake, or beach environment.
Uses & applications
Crushed granite is widely used in construction, road building, and aggregate. Polished slabs are popular for countertops, monuments, and landscaping stones. Small water-worn pebbles like this are collected, used in decorative gardens, or polished in rock tumblers.
Geological facts
Granite makes up a large portion of Continental Crust. The pinkish-red spots are potassium feldspar (orthoclase or microcline), while the greyish transparent grains are quartz, and darker specks are typically biotite or hornblende.
Field identification & locations
Easily identified by its salt-and-pepper or mottled pink-and-grey phaneritic texture with visible mineral grains of uniform size. Commonly found along stream beds, beaches, and glaciated areas across the world.
