igneous
Red Granite
Phaneritic Felsic Igneous Rock (Quartz, Alkali Feldspar, Plagioclase)
Hardness: 6-7 on Mohs scale; Color: Reddish-pink to deep rust-red with black and grey speckles; Luster: Dull to vitreous; Crystal structure: Phaneritic (visible coarse grains); Cleavage: Perfect on feldspar grains, none on quartz.
- Hardness
- 6-7 on Mohs scale
- Color
- Reddish-pink to deep rust-red with black and grey speckles
- Luster
- Dull to vitreous
Identified More igneous →
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Physical properties
Hardness: 6-7 on Mohs scale; Color: Reddish-pink to deep rust-red with black and grey speckles; Luster: Dull to vitreous; Crystal structure: Phaneritic (visible coarse grains); Cleavage: Perfect on feldspar grains, none on quartz.
Formation & geological history
Formed from the slow cooling of silica-rich magma deep underground (plutonic). This specimen likely dates from the Precambrian or Paleozoic eras and was brought to the surface through erosion and tectonic uplift.
Uses & applications
Extensively used in construction as dimension stone, countertops, monuments, and as aggregate for roads. High-quality pieces are used for ornamental carving.
Geological facts
The red color is caused by an abundance of potassium feldspar (orthoclase) containing trace impurities of iron oxide (hematite). Granite is one of the most common rocks in the Earth's continental crust.
Field identification & locations
Identified by its red/pink crystalline matrix interspersed with darker minerals (biotite or hornblende) and glassy quartz. Commonly found in batholiths and mountain ranges. It will not scratch with a steel knife but can scratch glass.
