mineral
Dumortierite Quartz
Dumortierite-bearing Quartz (SiO2 with Al7BO3(SiO4)3O3)
Hardness: 7 (quartz), Color: Blue to violet-blue, Luster: Vitreous to dull, Crystal Structure: Trigonal (quartz) with fibrous or columnar aggregates of dumortierite, Specific Gravity: 2.65 to 3.3 depending on inclusion density.
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Physical properties
Hardness: 7 (quartz), Color: Blue to violet-blue, Luster: Vitreous to dull, Crystal Structure: Trigonal (quartz) with fibrous or columnar aggregates of dumortierite, Specific Gravity: 2.65 to 3.3 depending on inclusion density.
Formation & geological history
Formed through regional metamorphism in aluminum-rich rocks, pegmatites, and hydrothermal veins. Often found in quartz veins traversing metamorphic or igneous rocks.
Uses & applications
Used frequently as a lapidary material for cabochons, carvings, beads, and ornamental items. Also collected as mineral specimens by enthusiasts.
Geological facts
Dumortierite is often mistaken for lapis lazuli or sodalite, but its hardness is notably higher because it is intergrown with quartz. It was named after the French paleontologist Eugène Dumortier.
Field identification & locations
Can be identified in the hand specimen by its distinct denim-blue or violet-blue coloration embedded within translucent quartz matrix. Commonly sourced from locations such as Madagascar, Namibia, Brazil, and the USA (Nevada).
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