igneous

Granite

Felsic Plutonic Rock (primarily Quartz, Potassium Feldspar, and Plagioclase)

Hardness: 6-7 (Mohs scale); Color: Pink (from orthoclase), grey (quartz), and black (biotite/hornblende); Luster: Vitreous to dull; Structure: Phaneritic (coarse-grained) crystalline; Cleavage: None (fractures irregularly); Specific gravity: 2.63 to 2.75

Hardness: 6-7 (Mohs scale)
Luster: Vitreous to dull

Identified June 2, 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 Earth's surface in large intrusions called batholiths. This specimen likely dates from the Precambrian to Cenozoic eras depending on the specific mountain range of origin.

Uses & applications

Extensively used in construction for countertops, floor tiles, paving stones, curbing, monuments, and as crushed stone for road base.

Geological facts

Granite makes up a large portion of the Earth's continental crust. Unlike oceanic crust which is basaltic, the continents stay afloat because granite is relatively low-density. Mount Rushmore is carved into a massive granite batholith.

Field identification & locations

Identify by its interlocking 'salt and pepper' or speckled crystalline texture where individual minerals are visible to the naked eye. Found globally in mountainous regions and continental shields like the Canadian Shield or the Appalachians.

Other igneous specimens

See all

Granite

Igneous

Granite

Igneous

Blue Apatite

Fluorapatite (Ca5(PO4)3F)

mineral

Dalmatian Jasper

Aplite with Arfvedsonite inclusions

igneous

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