igneous
Red Granite
Phaneritic Felsic Igneous Rock
Hardness: 6-7 Mohs; Color: Pinkish-red, grey, and black; Luster: Dull to vitreous; Crystal structure: Coarse-grained (phaneritic); Cleavage: Indistinct; Specific Gravity: 2.63-2.75
- Hardness
- 6-7 Mohs
- Color
- Pinkish-red, grey, and black
- Luster
- Dull to vitreous
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Physical properties
Hardness: 6-7 Mohs; Color: Pinkish-red, grey, and black; Luster: Dull to vitreous; Crystal structure: Coarse-grained (phaneritic); Cleavage: Indistinct; Specific Gravity: 2.63-2.75
Formation & geological history
Formed by the slow crystallization of magma below Earth's surface. The high potassium feldspar (orthoclase) content gives it the characteristic red color. These rocks can date back to various geological eras, often found in Precambrian shields.
Uses & applications
Extensively used as a dimension stone for monuments, countertops, flooring, and as crushed stone for construction and road bases.
Geological facts
Granite is one of the most common rocks in the Earth's continental crust. It is a 'plutonic' rock, meaning it cooled slowly at great depths, allowing minerals like quartz and feldspar to grow large enough to be seen with the naked eye.
Field identification & locations
Identify by its phaneritic (coarse) texture and the presence of quartz (translucent grey), feldspar (red/pink), and mica or hornblende (black). It is commonly found in mountain ranges and glacial deposits.
