igneous

Granite Pebble

Granite (Phaneritic intrusive igneous rock)

Hardness: 6-7 (Mohs scale); Color: Mottle gray, white, and black; Luster: Dull to vitreous; Crystal structure: Phaneritic (coarse-grained crystals of quartz, feldspar, and mica); Specific gravity: 2.63 to 2.75

Hardness: 6-7 (Mohs scale)
Color: Mottle gray, white, and black
Luster: Dull to vitreous

Identified March 3, 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 crystallization of magma below Earth's surface. This specific specimen has been smoothed by water erosion through fluvial (river) or glacial transport, making it a water-worn pebble.

Uses & applications

In pebble form, it is used for landscaping, decorative stone, and construction aggregate. In slab form, granite is widely used for countertops and monuments.

Geological facts

Granite makes up a large portion of the Earth's continental crust. Because of its hardness and resistance to acid, it is one of the most durable natural stones used by humans since ancient Egyptian times.

Field identification & locations

Identify by its 'salt and pepper' appearance and visible crystalline grains. Found globally in riverbeds, beaches, and mountainous regions. Collectors look for unique inclusions or high-contrast mineral banding.

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