igneous

Diorite

Diorite (Intermediate intrusive igneous rock)

Hardness: 6-7 on Mohs scale. Color: Salt-and-pepper (speckled black and white). Luster: Phaneritic (crystalline). Crystal structure: Monoclinic/Triclinic minerals. Specific gravity: 2.85-3.0.

Hardness: 6-7 on Mohs scale
Color: Salt-and-pepper (speckled black and white)
Luster: Phaneritic (crystalline)

Identified April 8, 2026More igneous →

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Physical properties

Hardness: 6-7 on Mohs scale. Color: Salt-and-pepper (speckled black and white). Luster: Phaneritic (crystalline). Crystal structure: Monoclinic/Triclinic minerals. Specific gravity: 2.85-3.0.

Formation & geological history

Formed by the slow cooling of magma beneath the Earth's surface in volcanic arcs and mountain-building zones. Often found above subduction zones.

Uses & applications

Commonly used as a base material in construction of roads and buildings. When polished, it is used as dimension stone for countertops and floor tiles. Historically used for sculpture due to its extreme durability.

Geological facts

The famous Code of Hammurabi, one of the oldest deciphered writings of significant length in the world, was inscribed onto a 7-foot tall diorite stele.

Field identification & locations

Identify by its phaneritic (visible crystals) coarse-grained texture and balanced speckled appearance. Unlike granite, it lacks significant quartz and has little to no pink potassium feldspar. Commonly found in roots of mountain ranges like the Andes.

Other igneous specimens

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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