igneous

Granite Pebble

Granite (composed primarily of Quartz, Feldspar, and Mica)

Hardness: 6-7 on Mohs scale; Color: Salt-and-pepper (tan, white, black, pink); Luster: Vitreous to dull; Crystal structure: Phaneritic (coarse-grained); Cleavage: None in the rock itself, though individual minerals may have it.

Hardness: 6-7 on Mohs scale
Color: Salt-and-pepper (tan, white, black, pink)
Luster: Vitreous to dull

Identified April 10, 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 silica-rich magma beneath the Earth's surface. This specimen appears to be a water-worn or weathered pebble fragment.

Uses & applications

Used extensively in construction for countertops, floor tiles, and gravel. On this scale, it is typically used as aggregate or landscaping stone.

Geological facts

Granite makes up a large portion of the Earth's continental crust. Because of its hardness and resistance to weathering, it is the primary material for the base of many ancient mountain ranges.

Field identification & locations

Identify by looking for a 'salt and pepper' appearance with distinct mineral grains visible to the naked eye. Commonly found in riverbeds, glacial deposits, and mountain ranges.

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