mineral

Dumortierite Quartz

Aluminum Borate Silicate Oxide (Al7BO3(SiO4)3O3)

AI-generated identification · may be incorrect

Hardness: 7 to 8.5 (Mohs), Color: Characteristic blue, violet-blue, or indigo, Luster: Vitreous to dull, Crystal structure: Orthorhombic, Cleavage: Good on {100}

Hardness: 7 to 8

Identified July 9, 2026More mineral →

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Physical properties

Hardness: 7 to 8.5 (Mohs), Color: Characteristic blue, violet-blue, or indigo, Luster: Vitreous to dull, Crystal structure: Orthorhombic, Cleavage: Good on {100}

Formation & geological history

Typically forms in regional metamorphic rocks rich in aluminum, such as gneiss or schist, and sometimes in boron-rich pegmatites and hydrothermally altered rocks.

Uses & applications

Used as a decorative stone, in jewelry (beads, cabochons), and in the production of high-grade porcelain and ceramics due to its high aluminum content.

Geological facts

It is often named 'Blue Quartz' when it occurs as inclusions in quartz. It was named after the French paleontologist Eugène Dumortier who first observed it in the late 19th century.

Field identification & locations

Identified by its distinct waxy to vitreous luster and deep blue color that does not streak. Common sources include Brazil, Madagascar, and Sri Lanka. Collectors look for pieces with high clarity or interesting fibrous inclusions.