metamorphic
Blue Quartzite (Aventurine)
Silicon Dioxide (SiO2) with Dumortierite or Crocidolite inclusions
Hardness: 7 (Mohs scale); Color: Blue to denim blue; Luster: Vitreous to waxy; Crystal Structure: Trigonal (microcrystalline); Cleavage: None; SG: 2.6-2.7
- Hardness
- 7 (Mohs scale)
- Color
- Blue to denim blue
- Luster
- Vitreous to waxy
Identified More metamorphic →
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Physical properties
Hardness: 7 (Mohs scale); Color: Blue to denim blue; Luster: Vitreous to waxy; Crystal Structure: Trigonal (microcrystalline); Cleavage: None; SG: 2.6-2.7
Formation & geological history
Formed through the regional metamorphism of quartz-rich sandstone. The blue color typically comes from the presence of tiny inclusions of fibrous minerals like dumortierite during the recrystallization process.
Uses & applications
Commonly used for tumbled stones, decorative beads, cabochons for jewelry, and as ornamental garden stones.
Geological facts
Blue aventurine is often called a 'stone of self-discipline.' Unlike Lapis Lazuli, it lack brassy pyrite flecks, and unlike Sodalite, it is much harder and lacks white calcite veining.
Field identification & locations
Identify by its hardness (will scratch glass) and its grainy, sugary texture visible under a lens. Found frequently in Brazil, India, and parts of Russia.
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