igneous

Granite

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

Hardness: 6-7 on Mohs scale. Color: Speckled white, pink, and grey with black minerals. Luster: Vitreous to dull. Crystal Structure: Coarse-grained (phaneritic) interlocking crystals. Cleavage: None (though individual minerals like feldspar have cleavage). Specific Gravity: 2.63 to 2.75.

Hardness: 6-7 on Mohs scale
Color: Speckled white, pink, and grey with black minerals
Luster: Vitreous to dull

Identified March 20, 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 by the slow crystallization of silica-rich magma beneath the Earth's surface (intrusive). Geological age varies from Precambrian to Cenozoic eras, typically associated with continental crust formation and mountain-building events.

Uses & applications

Widely used in construction for countertops, floor tiles, paving stones, and monuments. Also used as crushed stone for road base and railroad ballast. Minimal value in jewelry, primarily used for large-scale architectural projects.

Geological facts

Granite makes up a large part of the Earth's continental crust. Mount Rushmore is carved into a granite batholith. It is one of the hardest and most durable natural stones, which is why it has been used for monuments throughout human history.

Field identification & locations

Identify in the field by its 'salt and pepper' appearance and visible, interlocking crystals that do not show alignment or layers. Common in mountainous regions and glacial till. Collectors look for unique color variations or large crystal sizes (pegmatites).

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

Blue Apatite

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

mineral

Sodalite

Sodalite - Na8(Al6Si6O24)Cl2

mineral

Magnetite

Magnetite (Fe3O4)

mineral