igneous
Granite Pebble
Phaneritic Felsic Igneous Rock
Hardness: 6-7 on Mohs scale; Color: Mottled grey, white, and black; Luster: Dull to vitreous; Crystal Structure: Phaneritic (visible crystals of quartz, feldspar, and mica/amphibole); Specific Gravity: 2.63-2.75.
- Hardness
- 6-7 on Mohs scale
- Color
- Mottled grey, white, and black
- Luster
- Dull to vitreous
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Physical properties
Hardness: 6-7 on Mohs scale; Color: Mottled grey, white, and black; Luster: Dull to vitreous; Crystal Structure: Phaneritic (visible crystals of quartz, feldspar, and mica/amphibole); Specific Gravity: 2.63-2.75.
Formation & geological history
Formed from the slow cooling and crystallization of molten magma deep beneath the Earth's surface (plutonic). This specific specimen appears to be a water-worn or weathered pebble likely from the Cenozoic era, though the source rock could be billions of years old.
Uses & applications
Granite is used extensively in construction, countertops, monuments, and as crushed stone for road base. This small pebble has decorative value in landscaping or as a basic educational specimen.
Geological facts
Granite makes up a large portion of the Earth's continental crust. Unlike oceanic crust which is primarily basalt, continental crust is 'granitic'.
Field identification & locations
Identify by its 'salt and pepper' appearance and the presence of visible, interlocking minerals including translucent quartz and opaque feldspar. Commonly found in riverbeds, glacial tills, and mountainous regions.
