igneous
Granite (River-worn Pebble)
Phaneritic Igneous Rock (Granitic composition)
Hardness: 6-7 Mohs; Color: Mottled gray, pink, and black; Luster: Dull to vitreous; Crystal structure: Phaneritic (coarse-grained visible crystals); Specific gravity: 2.6-2.7 g/cm³.
- Hardness
- 6-7 Mohs
- Color
- Mottled gray, pink, and black
- Luster
- Dull to vitreous
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Physical properties
Hardness: 6-7 Mohs; Color: Mottled gray, pink, and black; Luster: Dull to vitreous; Crystal structure: Phaneritic (coarse-grained visible crystals); Specific gravity: 2.6-2.7 g/cm³.
Formation & geological history
Formed through the slow cooling and crystallization of silica-rich magma deep underground (plutonic). This specific specimen has been shaped and smoothed by water erosion in a river or glacial environment.
Uses & applications
Common granite is used extensively in construction, countertops, and road base. This small pebble is primarily a nature-collecting specimen or decorative garden stone.
Geological facts
Granite is the most common rock found in Earth's continental crust. The pink hue in this specimen suggests a high concentration of potassium feldspar (orthoclase).
Field identification & locations
Identify by looking for a 'salt and pepper' appearance with distinct mineral grains like quartz (clear/gray), feldspar (white/pink), and hornblende/biotite (black). Commonly found in mountain ranges and glacial deposits.
