Dumortierite Quartz
Dumortierite Quartz (Quartz with Dumortierite inclusions) · Semi-Precious Gemstone / Decorative Stone
Crystal System
Trigonal (Quartz host) / Orthorhombic (Dumortierite inclusions); polished massive habit
Mineral Group
Silicates (Tectosilicate host with Nesosilicate inclusions)
Chemical Formula
SiO2 (Quartz) with Al7(BO3)(SiO4)3O3 (Dumortierite)
Formation Process
Metamorphic or Magmatic (Hydrothermal); forms in aluminum-rich regional metamorphic rocks or pegmatites
About This Crystal
A deep blue to violet-blue tumbled stone with a waxy to vitreous luster. It is typically translucent to opaque with a mottled or 'denim' appearance caused by fibrous dumortierite inclusions within the quartz matrix.
Physical Characteristics
Color: Indigo blue to dark violet. Streak: White. Fracture: Conchoidal to uneven. Specific Gravity: 2.65-3.41. Fluorescence: Inert to weak blue.
Optical Properties
Refractive Index: 1.544-1.553. Birefringence: 0.009. Pleochroism: Strong (blue-violet to colorless) in pure crystals, though often masked in massive quartz forms.
Hardness & Durability
Origin Region
Brazil (Minas Gerais), South Africa, Madagascar, and Sri Lanka
Hardness & Durability
Mohs Hardness: 7 to 8.5 (quartz host is 7, dumortierite inclusions up to 8.5). Excellent durability for jewelry and handling.
Care & Maintenance
Wash with warm soapy water. Resistant to most chemicals but avoid extreme heat. Stable for sunlight exposure, unlike many other blue minerals.
Rarity & Value
Relatively Common; more valuable when deep blue and translucent. Often sold as tumbled stones or cabochons. Frequently used as a more affordable substitute for Lapis Lazuli.
Special Characteristics
Features a unique 'denim' texture. Unlike Sodalite or Lapis, it lacks white calcite or gold pyrite flecks, appearing more consistent and violet-toned.
Lore & History
First described in 1881 by Eugène Dumortier. In metaphysical lore, it is known as the 'Stone of Patience' and is associated with the Third Eye and Throat Chakras for mental clarity.