igneous
Granite Pebble
Granite (composed primarily of Quartz: SiO2, Feldspar: KAlSi3O8, and Mica: K(Mg,Fe)3AlSi3O10(OH)2)
Hardness: 6-7 Mohs; Color: Light gray, tan, or salt-and-pepper appearance; Luster: Vitreous to dull; Structure: Phaneritic (medium-grained crystalline); Cleavage: Irregular fracture in mass
- Hardness
- 6-7 Mohs
- Color
- Light gray, tan, or salt-and-pepper appearance
- Luster
- Vitreous to dull
Identified More igneous →
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Physical properties
Hardness: 6-7 Mohs; Color: Light gray, tan, or salt-and-pepper appearance; Luster: Vitreous to dull; Structure: Phaneritic (medium-grained crystalline); Cleavage: Irregular fracture in mass
Formation & geological history
Formed from the slow cooling of magma beneath the Earth's surface (intrusive). This specific pebble was later rounded by water/erosion in a riverbed or coastal environment.
Uses & applications
Commonly used in large scale for construction, countertops, and road base. In pebble form, used for landscaping and decorative garden features.
Geological facts
Granite makes up much of the Earth's continental crust; it is incredibly durable and resistant to acid, which is why it occupies such high importance in architecture.
Field identification & locations
Identify in the field by its speckled 'salt and pepper' appearance and its inability to be scratched by a steel pocketknife. Found globally in mountainous or glaciated regions.
