Rock Identifier
Red Granite (Phaneritic Felsic Igneous Rock (composed of Quartz, Alkali Feldspar, and Plagioclase)) — igneous
igneous

Red Granite

Phaneritic Felsic Igneous Rock (composed of Quartz, Alkali Feldspar, and Plagioclase)

Hardness: 6-7 Mohs; Color: Pinkish-red to deep reddish-brown; Luster: Vitreous to dull; Crystal structure: Phaneritic (coarse-grained); Cleavage: Perfect in feldspars, none in quartz; Specific Gravity: 2.63 - 2.75

Hardness
6-7 Mohs
Color
Pinkish-red to deep reddish-brown
Luster
Vitreous to dull
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Physical properties

Hardness: 6-7 Mohs; Color: Pinkish-red to deep reddish-brown; Luster: Vitreous to dull; Crystal structure: Phaneritic (coarse-grained); Cleavage: Perfect in feldspars, none in quartz; Specific Gravity: 2.63 - 2.75

Formation & geological history

Formed through the slow cooling of silica-rich magma deep underground. The red color is typically caused by the presence of potassium feldspar (orthoclase) and may be enhanced by trace amounts of hematite iron oxide. Geological age varies by location from Precambrian to Cenozoic.

Uses & applications

Extensively used in construction as dimension stone, kitchen countertops, monuments, curbing, and decorative landscaping. High-quality red variants are popular for gravestones and architectural cladding.

Geological facts

Granite makes up a large portion of the Earth's continental crust. Famous examples of red granite include the Aswan Granite used in Ancient Egyptian obelisks and the 'Texas Red' granite used for the Texas State Capitol.

Field identification & locations

Identify in the field by its interlocking mineral crystals and granular texture. Look for visible glassy quartz and pink/red rectangular feldspar crystals. It is found in mountain ranges and continental shields worldwide.

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