igneous

Granite

Granite (compositional mixture of Quartz, Feldspar, and Mica)

Hardness: 6-7 on Mohs scale; Color: Mottled grey, white, and tan; Luster: Dull to vitreous; Structure: Phaneritic (coarse-grained crystalline); Cleavage: None (individual minerals within have cleavage, but the rock fractures irregularly).

Hardness: 6-7 on Mohs scale
Color: Mottled grey, white, and tan
Luster: Dull to vitreous

Identified March 25, 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 crystallization of silica-rich magma below the Earth's surface (intrusive). Geological age varies globally from Archean to Cenozoic eras.

Uses & applications

Extensively used in construction for countertops, floor tiles, paving stones, curbing, and as aggregate in road building. Also used for monuments and sculptures.

Geological facts

Granite makes up a large portion of the Earth's continental crust. It is one of the hardest and most durable natural stones, which is why it has been used since Ancient Egypt for massive obelisks and temple structures.

Field identification & locations

Identify in the field by its 'salt and pepper' appearance and visible interlocking crystals. It is ubiquitous in mountain ranges and continental shields. Collectors should look for specimens with large phenocrysts or unusual mineral inclusions.

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