igneous

Granitic Pegmatite

Granite (with coarse-grained Quartz, Feldspar, and Mica components)

Hardness: 6-7 (Mohs scale); Color: Mottled white, gray, and pink/tan with dark flecks; Luster: Vitreous to pearly; Crystal structure: Phaneritic (large, visible crystals); Cleavage: Perfect in feldspar and mica inclusions; Specific gravity: 2.6-2.7

Hardness: 6-7 (Mohs scale)
Color: Mottled white, gray, and pink/tan with dark flecks
Luster: Vitreous to pearly

Identified March 5, 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 from the slow cooling of magma deep within the Earth's crust, allowing large crystals to grow. Typically found in Plutonic environments and ancient continental shields.

Uses & applications

Used in construction as crushed stone, architectural facades, and countertops. Also a source of industrial minerals like quartz and mica.

Geological facts

Pegmatites are known for containing the largest crystals of any rock type on Earth. This specimen shows a mix of milky quartz and alkaline feldspar.

Field identification & locations

Identify in the field by its coarse, 'salt and pepper' crystalline texture and extreme hardness (cannot be scratched by a steel knife). Commonly found in mountain ranges and glacial till.

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