igneous
Granite Water-Worn Pebble
Phaneritic Felsic Igneous Rock (Granite)
Hardness: 6-7 Mohs; Color: Pink, white, and black mottled; Luster: Vitreous to dull; Crystal structure: Phaneritic (coarse-grained); Cleavage: Indistinct; Specific gravity: 2.63 to 2.75
- Hardness
- 6-7 Mohs
- Color
- Pink, white, and black mottled
- Luster
- Vitreous to dull
Identified More igneous →
Explore Granite Water-Worn Pebble in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 6-7 Mohs; Color: Pink, white, and black mottled; Luster: Vitreous to dull; Crystal structure: Phaneritic (coarse-grained); Cleavage: Indistinct; Specific gravity: 2.63 to 2.75
Formation & geological history
Formed from the slow cooling of silica-rich magma deep underground. This specific specimen has been physically weathered and rounded by river action. Geological age can range from millions to billions of years old.
Uses & applications
Larger deposits are used for construction, countertops, and monuments; as a river pebble, it is used for landscaping, aquarium decor, and pocket stones.
Geological facts
Granite is the most common rock in Earth's continental crust. The pink color in this specimen comes from potassium feldspar (orthoclase).
Field identification & locations
Look for a salt-and-pepper or mottled appearance with visible interlocking crystals of quartz and feldspar. Commonly found in riverbeds, glacial tills, and mountain outcrops. Hardness allows it to scratch glass.
