igneous

Diorite (weathered)

Intermediate plutonic igneous rock

Hardness: 6-7 on Mohs scale; Color: Salt and pepper (mottled black/white/grey/green) with brown iron staining; Luster: Dull to phaneritic; Structure: Granular/Crystalline; Cleavage: Good in feldspar crystals.

Hardness: 6-7 on Mohs scale
Luster: Dull to phaneritic

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 cooling of magma below the Earth's surface in volcanic arcs or orogenic belts. This specific specimen shows oxidative weathering (rust-colored staining) from exposure to air and water.

Uses & applications

Used primarily in construction as crushed stone or 'road base'. High-quality varieties are polished for use as architectural stone, countertops, or cemetery monuments.

Geological facts

Diorite was used by Ancient Egyptians for statues and vases because of its extreme hardness and durability; the Code of Hammurabi was famously inscribed on a diorite stele.

Field identification & locations

Identify by its coarse-grained 'salt and pepper' appearance and lack of visible quartz compared to granite. It is commonly found in mountain ranges such as the Andes, or across the Cascades in the US.

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