mineral

Blue Dumortierite Quartz

AlAl6BSi3O18 (Dumortierite) within SiO2 (Quartz)

Hardness: 7 (Quartz) to 8.5 (Dumortierite); Color: Blue to violet-blue in a greyish matrix; Luster: Vitreous to waxy; Crystal structure: Orthorhombic (fibrous inclusions); Specific gravity: 2.65-3.41

Hardness: 7 (Quartz) to 8
Color: Blue to violet-blue in a greyish matrix
Luster: Vitreous to waxy

Identified May 18, 2026More mineral →

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Physical properties

Hardness: 7 (Quartz) to 8.5 (Dumortierite); Color: Blue to violet-blue in a greyish matrix; Luster: Vitreous to waxy; Crystal structure: Orthorhombic (fibrous inclusions); Specific gravity: 2.65-3.41

Formation & geological history

Formed in aluminum-rich regional metamorphic rocks (schists and gneisses) and occasionally in granitic pegmatites. The blue color is caused by the inclusion of fibrous Dumortierite minerals within the quartz matrix.

Uses & applications

Primarily used as a semi-precious gemstone for jewelry, ornamental carvings, and 'worry stones'. Industrially, pure dumortierite is used in the manufacture of high-grade porcelain.

Geological facts

Dumortierite was first described in 1881 for an occurrence in Chaponost, France, and was named after the French paleontologist Eugène Dumortier. It is often mistaken for Sodalite or Lapis Lazuli but is significantly harder.

Field identification & locations

Identify by its distinct blue fibrous inclusions and superior hardness compared to sodalite. It is commonly found in Madagascar, Brazil, and the United States (Nevada). Collectors look for deep indigo saturation and high translucency.

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