igneous
Granite (River Cobble)
Phaneritic Plutonic Felsic Rock (Granite)
Hardness: 6-7 Mohs; Color: Salt-and-pepper (white, grey, black); Luster: Vitreous to dull; Crystal structure: Phaneritic (coarse crystals); Cleavage: Indistinct; Specific Gravity: 2.63-2.75
- Hardness
- 6-7 Mohs
- Color
- Salt-and-pepper (white, grey, black)
- Luster
- Vitreous to dull
Identified More igneous →
Explore Granite (River Cobble) in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 6-7 Mohs; Color: Salt-and-pepper (white, grey, black); Luster: Vitreous to dull; Crystal structure: Phaneritic (coarse crystals); Cleavage: Indistinct; Specific Gravity: 2.63-2.75
Formation & geological history
Formed through the slow crystallization of magma below Earth's surface. This specific specimen has been smoothed and rounded by water erosion in a river or coastal environment.
Uses & applications
Used in construction, countertops, monuments, and as decorative landscaping stones. Highly valued for durability and aesthetics.
Geological facts
Granite makes up a large portion of the Earth's continental crust. It is primarily composed of quartz, feldspar, and mica (the black flecks).
Field identification & locations
Identify in the field by its visible interlocking crystals of white/clear quartz and opaque feldspar. Commonly found in mountain ranges and as water-worn pebbles in drainage basins.
