Pink Granite (River Pebble)

Physical Properties

Hardness: 6–7 Mohs; Color: Pink, white, and translucent gray with dark specks; Luster: Vitreous to dull; Crystal structure: Phaneritic (coarse-grained); Composition: Orthoclase feldspar, quartz, and minor mica/amphibole.

Formation & Geological History

Formed from the slow cooling of silica-rich magma deep beneath the Earth's surface (plutonic). This specimen appears water-worn, suggesting it was transported by a river or stream after erosion from a larger batholith.

Uses & Applications

Used widely in construction as crushed stone, dimension stone for countertops and monuments, and as decorative landscaping gravel.

Geological Facts

Granite is the primary component of Earth's continental crust. Its pink color specifically comes from a high concentration of potassium feldspar (orthoclase).

Field Identification & Locations

Identify by its interlocking crystalline texture and lack of layering. It cannot be scratched by a steel knife. Common in mountainous regions or glacial deposits.

Identified on: 4/14/2026

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