mineral

Blue Dumortierite Quartz

Dumortierite in Quartz (AlAl6BSi3O12(O,OH)3)

Hardness: 7.0 (Quartz) to 8.5 (Dumortierite); Color: Indigo blue to violet-blue; Luster: Vitreous to waxy; Crystal Structure: Orthorhombic fibers within trigonal quartz; Cleavage: Poor; Specific Gravity: 3.26-3.41

Hardness: 7
Color: Indigo blue to violet-blue
Luster: Vitreous to waxy

Identified May 23, 2026More mineral →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Formation & geological history

Forms in regional metamorphic rocks such as gneisses and schists, often as a result of boron-rich hydrothermal activity. This specimen is a tumbled piece of quartz containing fibrous dumortierite inclusions.

Uses & applications

Primarily used as a semi-precious gemstone in jewelry, for decorative tumbled stones, and as a collector's mineral specimen. Some is used in the manufacture of high-grade porcelain and ceramics.

Geological facts

It was first described in 1881 for an occurrence in Chaponost, France, and named after the French paleontologist Eugène Dumortier. It is often mistaken for sodalite or lapis lazuli but is significantly harder.

Field identification & locations

Identify in the field by its distinct violet-blue color and hardness (it can scratch glass). It is commonly found in Brazil, Madagascar, and South Africa. Collectors look for intense blue saturation and clarity of the quartz matrix.

Other mineral specimens

See all

Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

sedimentary

Epidote

Epidote | Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)

metamorphic

Nephrite Jade

Nephrite

Mineral/Rock

Banded Gneiss (River Rock/Pebble)

Gneiss (specifically a banded variety often found as a river rock)

Metamorphic Rock

Biotite Schist

Biotite-rich Schist [K(Mg,Fe)3AlSi3O10(F,OH)2]

metamorphic

Green Apatite on Albite

Fluorapatite [Ca5(PO4)3F] on Albite [Na(AlSi3O8)]

mineral