igneous
Granite Pebble
Granite (Phaneritic intrusive igneous rock consisting of Quartz, Alkali Feldspar, and Plagioclase)
Hardness: 6-7 on Mohs scale; Color: Salt-and-pepper (mottled grey, white, and black); Luster: Vitreous to dull; Crystal structure: Phaneritic (coarse-grained visible crystals); Specific gravity: 2.63 - 2.75
- Hardness
- 6-7 on Mohs scale
- Color
- Salt-and-pepper (mottled grey, white, and black)
- Luster
- Vitreous to dull
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Physical properties
Hardness: 6-7 on Mohs scale; Color: Salt-and-pepper (mottled grey, white, and black); Luster: Vitreous to dull; Crystal structure: Phaneritic (coarse-grained visible crystals); Specific gravity: 2.63 - 2.75
Formation & geological history
Formed from the slow crystallization of magma below Earth's surface. This specific specimen shows signs of mechanical weathering and erosion, likely in a riverbed or coastal environment, which rounded its edges over thousands of years.
Uses & applications
Commonly used as construction aggregate, road base, or decorative landscaping stones. Larger slabs are used for countertops and monuments.
Geological facts
Granite makes up a large portion of the Earth's continental crust. Because it is very hard and resistant to acid rain, it is the preferred material for outdoor statues and gravestones.
Field identification & locations
Identify in the field by its 'salt and pepper' appearance and the presence of interlocking crystals of quartz and feldspar. Found globally in mountainous regions or as glacial till and river gravel in lower elevations.
