igneous
Granite
Intrusive igneous rock (Granite)
Hardness: 6-7 on Mohs scale. Color: Mottled orange, tan, and black. Luster: Dull to phaneritic. Crystal structure: Phaneritic (coarse-grained). Specific gravity: 2.63–2.75.
- Hardness
- 6-7 on Mohs scale
- Color
- Mottled orange, tan, and black
- Luster
- Dull to phaneritic
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Physical properties
Hardness: 6-7 on Mohs scale. Color: Mottled orange, tan, and black. Luster: Dull to phaneritic. Crystal structure: Phaneritic (coarse-grained). Specific gravity: 2.63–2.75.
Formation & geological history
Formed through the slow crystallization of magma below Earth's surface (intrusive). The orange hue in this specimen suggests oxidation of iron-bearing minerals or a high concentration of potassium feldspar (orthoclase).
Uses & applications
Used widely in construction for countertops, floor tiles, paving stone, curbing, and monument building because of its durability.
Geological facts
Granite makes up a large part of the Earth's continental crust. It is one of the hardest and most common rocks found on the planet's surface.
Field identification & locations
Identified by its visible interlocking crystals of quartz, feldspar, and mica. This piece is water-worn, likely found in a riverbed or coastal area. Common globally in mountainous regions.
