igneous

Granite

Phaneritic Felsic Igneous Rock (primarily Quartz, Feldspar, and Mica)

Hardness: 6–7 on Mohs scale; Color: Speckled gray, white, and black; Luster: Vitreous to dull; Crystal structure: Phaneritic (large, visible interlocking grains); Cleavage: Indistinct; Specific gravity: 2.63 - 2.75

Hardness: 6–7 on Mohs scale
Color: Speckled gray, white, and black
Luster: Vitreous to dull

Identified March 31, 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 through the slow crystallization of magma below the Earth's surface (intrusive). They are typically found in batholiths and continental crust, with ages ranging from billions of years (Precambrian) to more recent tectonic events.

Uses & applications

Extensively used in construction as dimension stone, floor tiles, kitchen countertops, and as crushed stone for road base or railway ballast.

Geological facts

Granite is the most common rock in the Earth's continental crust. Mount Rushmore is carved into a massive granite batholith in the Black Hills of South Dakota.

Field identification & locations

Identify in the field by its interlocking 'salt and pepper' crystalline texture and extreme hardness (cannot be scratched by a steel blade). Common in mountain ranges and eroded shield areas worldwide.

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