mineral

Blue Dumortierite in Quartz

Al7(BO3)(SiO4)3O3 (Dumortierite)

AI-generated identification · may be incorrect

Hardness: 7 (in quartz), 7-8.5 (pure mineral); Color: Dark blue, violet-blue, or indigo; Luster: Vitreous to dull; Crystal structure: Orthorhombic; Specific Gravity: 3.26–3.41

Hardness: 7 (in quartz), 7-8
Color: Dark blue, violet-blue, or indigo
Luster: Vitreous to dull

Identified July 2, 2026More mineral →

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Physical properties

Hardness: 7 (in quartz), 7-8.5 (pure mineral); Color: Dark blue, violet-blue, or indigo; Luster: Vitreous to dull; Crystal structure: Orthorhombic; Specific Gravity: 3.26–3.41

Formation & geological history

Formed in aluminum-rich regional metamorphic rocks, as well as in contact metamorphic rocks and boron-rich pegmatites.

Uses & applications

Used in the manufacture of high-grade porcelain, spark plugs, and ceramics due to its high resistance to heat; also used as a gemstone and for lapidary items like tumbled stones and carvings.

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 due to its deep blue color.

Field identification & locations

Identify by its distinct fibrous to massive habits and deep blue color that is often mottled within a translucent quartz matrix. Commonly found in Madagascar, Brazil, and the USA (Nevada).