igneous
Red Granite
Phaneritic Felsic Igneous Rock (Granite)
Hardness: 6-7 on Mohs scale. Color: Deep red to pinkish-red due to high potassium feldspar content, with flecks of gray (quartz) and black (biotite/amphibole). Luster: Dull to vitreous. Crystal structure: Phaneritic (coarse-grained).
- Hardness
- 6-7 on Mohs scale
- Luster
- Dull to vitreous
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Physical properties
Hardness: 6-7 on Mohs scale. Color: Deep red to pinkish-red due to high potassium feldspar content, with flecks of gray (quartz) and black (biotite/amphibole). Luster: Dull to vitreous. Crystal structure: Phaneritic (coarse-grained).
Formation & geological history
Formed from the slow cooling and crystallization of molten magma deep beneath the Earth's surface (plutonic). Found in ancient continental cratons, often dating back hundreds of millions to billions of years.
Uses & applications
Extensively used in construction for countertops, floor tiles, paving stones, and memorial monuments. Also used as crushed stone for road base and railroad ballast.
Geological facts
The red color is specifically attributed to iron oxide staining or high concentrations of orthoclase feldspar. Famous red granites include the Missouri Red Granite and various Egyptian granites used in ancient obelisks.
Field identification & locations
Identify by its interlocking crystalline texture and lack of layering. It is significantly harder than sedimentary rocks like sandstone. Commonly found in mountainous regions or areas with exposed continental shields like the Canadian Shield or the Scottish Highlands.
