igneous

Granite Pebble

Granite (Felsic Intrusive Igneous Rock)

Hardness: 6-7 Mohs; Color: Salt and pepper appearance with grey, white, pink, and black; Luster: Vitreous to dull; Crystal structure: Phaneritic (visible crystals); Cleavage: None (fractures irregularly); Specific gravity: 2.63-2.75.

Hardness: 6-7 Mohs
Color: Salt and pepper appearance with grey, white, pink, and black
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. This specimen appears to be a water-worn or tumbled pebble, likely formed millions of years ago in a batholith before being eroded and rounded by river or glacial action.

Uses & applications

Used extensively in construction (countertops, tiles), as aggregate in road building, and in landscaping. Polished pebbles are often used in decorative garden features or aquariums.

Geological facts

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

Field identification & locations

Identify by its interlocking crystal texture and the presence of quartz (grey/glassy), feldspar (white/pink), and mica or hornblende (black spots). Common in mountainous regions and riverbeds.

Other igneous specimens

See all

Granite

Igneous

Granite

Igneous

Blue Apatite

Fluorapatite (Ca5(PO4)3F)

mineral

Dalmatian Jasper

Aplite with Arfvedsonite inclusions

igneous

Magnetite

Iron(II,III) oxide (Fe3O4)

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