igneous
Red Granite
Phaneritic Felsic Igneous Rock (Granite)
Hardness: 6-7 Mohs; Color: Pink to deep red due to potassium feldspar (orthoclase), with black biotite or hornblende and translucent quartz; Luster: Dull to vitreous; Crystal Structure: Phaneritic (coarse-grained visible crystals); Specific Gravity: 2.63-2.75
- Hardness
- 6-7 Mohs
- Luster
- Dull to vitreous
Identified More igneous →
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Physical properties
Hardness: 6-7 Mohs; Color: Pink to deep red due to potassium feldspar (orthoclase), with black biotite or hornblende and translucent quartz; Luster: Dull to vitreous; Crystal Structure: Phaneritic (coarse-grained visible crystals); Specific Gravity: 2.63-2.75
Formation & geological history
Formed by the slow crystallization of magma below Earth's surface (intrusive). The red hue indicates a high concentration of alkali feldspar. These formations range from hundreds of millions to billions of years old.
Uses & applications
Used extensively in construction for countertops, floor tiles, paving stones, and monuments. Also popular in landscaping and as decorative gravel or polished specimens for collectors.
Geological facts
Red granite is often associated with the Precambrian Era. One of the most famous varieties is Aswan Granite from Egypt, which was used by ancient civilizations to construct obelisks and the interior of the Great Pyramid of Giza.
Field identification & locations
Identify by its interlocking 'salt and pepper' texture where the 'salt' is red/pink. It cannot be scratched by a steel knife. Commonly found in continental crust areas, glacial tills, and riverbeds near mountainous regions.
