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 May 25, 2026More igneous →

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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.

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