igneous

Coarse-grained Granite

Granitoid (KAlSi3O8 + SiO2 + NaAlSi3O8)

Hardness: 6-7 on Mohs scale; Color: Phaneritic mixture of pink/tan (potassium feldspar), white (plagioclase), and gray/translucent (quartz); Luster: Vitreous to pearly; Crystal structure: Crystal grains are easily visible to the naked eye (phaneritic texture).

Hardness: 6-7 on Mohs scale
Luster: Vitreous to pearly

Identified March 22, 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 cooling of silica-rich magma deep underground (plutonic formation) over millions of years. This specimen shows large interlocking crystals characteristic of intrusive igneous processes.

Uses & applications

Used extensively in construction for countertops, floor tiles, and gravel. It is also a primary material for monuments, bridges, and paving due to its durability and resistance to weathering.

Geological facts

Granite makes up a large portion of the Earth's continental crust. It is often found in the roots of mountain ranges where erosion has exposed the deep-seated 'plutons'. Famous examples include the peaks of Yosemite and the White Mountains.

Field identification & locations

Identify in the field by looking for a 'salt and pepper' or multi-colored speckled appearance with hard, scratch-resistant mineral grains. Commonly found in mountainous regions or glacial deposits. Collectors look for unique inclusions or rare accessory minerals like tourmaline.

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