igneous

Red Granite

Phaneritic Plutonic Rock (High Potassium Feldspar)

Hardness: 6-7 (Mohs scale); Color: Pink to reddish-orange with black and translucent grains; Luster: Dull to vitreous; Crystal structure: Phaneritic (coarse-grained crystals visible to the naked eye); Cleavage: Perfect in two directions for feldspar components; Specific gravity: 2.63 to 2.75

Hardness: 6-7 (Mohs scale)
Color: Pink to reddish-orange with black and translucent grains
Luster: Dull to vitreous

Identified March 21, 2026More igneous →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Formation & geological history

Formed from the slow cooling and crystallization of silica-rich magma deep underground (plutonic). The reddish hue is caused by a high concentration of potassium-rich orthoclase feldspar. Geological ages vary widely from Precambrian to Cenozoic eras.

Uses & applications

Extensively used as a building material, dimension stone for monuments, kitchen countertops, and as crushed stone for road construction and railroad ballast.

Geological facts

The red color often indicates a terrestrial or 'S-type' granite origin. Some of the most famous red granites come from Aswan, Egypt, and were used by ancient civilizations to construct obelisks and the inner chambers of pyramids.

Field identification & locations

Identify in the field by its speckled, 'salt and pepper' appearance with prominent pink/red minerals. It will not react with acid like limestone and is hard enough to scratch glass. Found globally in continental crust, particularly in mountain ranges and Canadian Shield areas.

Other igneous specimens

See all

Blue Apatite

Fluorapatite (Ca5(PO4)3F)

mineral

Dark Igneous Rock (Likely Basalt or Diabase)

Basalt (extrusive igneous rock) or Diabase (intrusive igneous rock - also known as Dolerite), largely composed of plagioclase feldspar, pyroxene (augite), and sometimes olivine and amphibole. Exact mineralogy would require thin section analysis.

Igneous

Magnetite

Iron(II,III) oxide (Fe3O4)

mineral

Sodalite

Sodalite - Na8(Al6Si6O24)Cl2

mineral

Blue Apatite

Apatite (Group), Ca5(PO4)3(F,Cl,OH)

mineral

Magnetite

Magnetite (Fe3O4)

mineral