igneous
Coarse-grained Granite or Gneiss
Granitic intrusive rock
Hardness: 6-7 Mohs; Color: Tan, white, and rusty orange/brown due to oxidation; Luster: Dull to sub-vitreous; Texture: Phaneritic (visible crystals); Composition: Quartz, Feldspar, and Mica.
- Hardness
- 6-7 Mohs
- Color
- Tan, white, and rusty orange/brown due to oxidation
- Luster
- Dull to sub-vitreous
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Physical properties
Hardness: 6-7 Mohs; Color: Tan, white, and rusty orange/brown due to oxidation; Luster: Dull to sub-vitreous; Texture: Phaneritic (visible crystals); Composition: Quartz, Feldspar, and Mica.
Formation & geological history
Formed through the slow cooling of silica-rich magma deep underground. The rusty coloring suggests weathering and oxidation of iron-bearing minerals over time.
Uses & applications
Used in construction, gravel, landscaping, and as a common decorative stone when polished.
Geological facts
Granite is the most common rock found in the Earth's continental crust. Its durability makes it a staple for monuments and building materials throughout history.
Field identification & locations
Identify by its interlocking crystalline texture and inability to be scratched by a steel knife. Common in mountainous regions and glacial deposits.
