igneous/metamorphic
Blue Quartz with Dumortierite/Magnesio-riebeckite inclusions
Quartz (SiO2) containing Dumortierite (Al7(BO3)(SiO4)3O3)
Hardness: 7 (Mohs scale). Color: Light grey-white base with streaks/haze of denim blue. Luster: Vitreous/Glassy. Crystal Structure: Hexagonal (trigonal). Cleavage: None. Specific Gravity: ~2.65.
- Hardness
- 7 (Mohs scale)
- Color
- Light grey-white base with streaks/haze of denim blue
- Luster
- Vitreous/Glassy
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Physical properties
Hardness: 7 (Mohs scale). Color: Light grey-white base with streaks/haze of denim blue. Luster: Vitreous/Glassy. Crystal Structure: Hexagonal (trigonal). Cleavage: None. Specific Gravity: ~2.65.
Formation & geological history
Formed in igneous pegmatites or metamorphic environments where silica-rich fluids crystallized under pressure alongside boron-rich minerals like dumortierite. This material often dates back to the Proterozoic or Paleozoic eras depending on the specific location.
Uses & applications
Used primarily as decorative stone, in lapidary work for cabochons or beads, and as a collector specimen. It is also used in the metaphysical community as a 'calming stone'.
Geological facts
Unlike Sapphire or Lapis, the blue in this quartz is caused by microscopic inclusions of other minerals rather than chemical substitution in the quartz lattice itself. Some notable deposits are found in the Ante-Cordillera mountains.
Field identification & locations
Identify in the field by its distinct hardness (can scratch glass) and the blue coloration that appears as 'clouds' or fibers within a translucent quartz host. Common locations include Brazil, South Africa, and Virginia, USA. For collectors, look for deep saturations of blue.
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