mineral
Dumortierite Quartz
Aluminum Borate Silicate Oxide (Al7BO3(SiO4)3O3)
AI-generated identification · may be incorrectHardness: 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
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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.
