metamorphic
Dumortierite Quartz
Dumortierite-bearing Quartz (Al7BO3(SiO4)3O3)
Hardness: 7.0 (Quartz mass) to 8.5 (Pure crystals); Color: Denim blue, violet-blue, or teal; Luster: Vitreous to dull; Crystal structure: Orthorhombic (as inclusions in Hexagonal quartz); Cleavage: Poor
- Hardness
- 7
- Color
- Denim blue, violet-blue, or teal
- Luster
- Vitreous to dull
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Physical properties
Hardness: 7.0 (Quartz mass) to 8.5 (Pure crystals); Color: Denim blue, violet-blue, or teal; Luster: Vitreous to dull; Crystal structure: Orthorhombic (as inclusions in Hexagonal quartz); Cleavage: Poor
Formation & geological history
Formed in high-temperature aluminum-rich regional metamorphic rocks, as well as in boron-bearing pegmatites and contact metamorphic rocks.
Uses & applications
Used primarily as a decorative stone, for cabochons in jewelry, carvings, and as a source for high-grade porcelain in industrial 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 Lapis Lazuli or Sodalite, but it is much harder.
Field identification & locations
Identify in the field by its distinct denim blue color and high hardness (it will easily scratch glass). Common locations include Brazil, Madagascar, South Africa, and the USA (Nevada).
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