igneous
Granite Pebble
Phaneritic plutonic rock (Quartz, Feldspar, Mica)
Hardness: 6-7 on Mohs scale; Color: Salt and pepper (shades of grey, white, and black); Luster: Dull to vitreous; Crystal structure: Phaneritic (visible crystals); Cleavage: Predominantly absent in bulk; Specific gravity: 2.63 to 2.75.
- Hardness
- 6-7 on Mohs scale
- Color
- Salt and pepper (shades of grey, white, and black)
- Luster
- Dull to vitreous
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Physical properties
Hardness: 6-7 on Mohs scale; Color: Salt and pepper (shades of grey, white, and black); Luster: Dull to vitreous; Crystal structure: Phaneritic (visible crystals); Cleavage: Predominantly absent in bulk; Specific gravity: 2.63 to 2.75.
Formation & geological history
Formed from the slow crystallization of magma below the Earth's surface. This specific specimen has been rounded and smoothed by water erosion in a river or beach environment over thousands of years.
Uses & applications
While large granite deposits are used in construction, countertops, and monuments, small pebbles like this are used in landscaping, aquarium decor, or as smoothing stones. Higher quality polished pieces can be used in jewelry.
Geological facts
Granite makes up a large portion of the Earth's continental crust. It is extremely durable and resistant to acid rain, making it a preferred material for outdoor memorials and buildings.
Field identification & locations
Identify in the field by its speckled appearance and 'salt and pepper' look. It is extremely hard and cannot be scratched by a steel knife. Commonly found in mountainous regions or along coastal/riverine areas where erosion has transported the material.
