igneous
Granite Pebble
Phaneritic Felsic Igneous Rock
Hardness: 6-7 on Mohs scale; Color: Mottled white, grey, and black; Luster: Dull to vitreous; Crystal structure: Phaneritic (visible crystals); Cleavage: None (fractures); Specific gravity: 2.63–2.75
- Hardness
- 6-7 on Mohs scale
- Color
- Mottled white, grey, and black
- Luster
- Dull to vitreous
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Physical properties
Hardness: 6-7 on Mohs scale; Color: Mottled white, grey, and black; Luster: Dull to vitreous; Crystal structure: Phaneritic (visible crystals); Cleavage: None (fractures); Specific gravity: 2.63–2.75
Formation & geological history
Formed from the slow cooling of silica-rich magma deep underground (plutonic). This specimen appears to be water-worn into a pebble shape over thousands of years.
Uses & applications
Used in construction, countertops, monuments, and as decorative landscaping stones.
Geological facts
Granite makes up a large portion of the Earth's continental crust. Its name comes from the Latin 'granum', meaning a grain, in reference to its coarse-grained structure.
Field identification & locations
Identify by its 'salt and pepper' appearance and visible interlocking crystals of quartz and feldspar. Commonly found in riverbeds, glacial tills, and mountainous regions.
