igneous

Granite

Granite (Mainly Quartz, Alkali Feldspar, and Plagioclase)

Hardness: 6-7 on Mohs scale; Color: Light gray to tan with salt-and-pepper flecks; Luster: Dull to vitreous; Structure: Phaneritic (coarse-grained); Specific Gravity: 2.63 to 2.75.

Hardness: 6-7 on Mohs scale
Color: Light gray to tan with salt-and-pepper flecks
Luster: Dull to vitreous

Identified April 9, 2026More igneous →

Identify your own rocks.

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

App Store Google Play

Physical properties

Hardness: 6-7 on Mohs scale; Color: Light gray to tan with salt-and-pepper flecks; Luster: Dull to vitreous; Structure: Phaneritic (coarse-grained); Specific Gravity: 2.63 to 2.75.

Formation & geological history

Formed from the slow crystallization of magma below Earth's surface. It is a plutonic rock found in continental crust, often dating from the Precambrian to Cenozoic eras.

Uses & applications

Used extensively in construction (curbing, pavers), interior design (countertops, floor tiles), and as dimension stone for monuments and public buildings.

Geological facts

Granite makes up a large part of the Earth's continental crust. Mount Rushmore is carved into a granite batholith in the Black Hills of South Dakota.

Field identification & locations

Identify in the field by its interlocking visible crystals of light-colored minerals (quartz/feldspar) and dark minerals (biotite/amphibole). It is found globally in mountain ranges and eroded 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