Dumortierite Quartz
Dumortierite inclusions in Quartz · Semi-Precious Gemstone / Mineral Specimen
Crystal System
Orthorhombic (Dumortierite) / Trigonal (Quartz); typically found in massive or fibrous habits
Mineral Group
Silicates (Nesosilicates for Dumortierite; Tectosilicates for Quartz)
Chemical Formula
AlAl6BSi3O18 (Dumortierite) in SiO2 (Quartz)
Formation Process
Metamorphic or Hydrothermal; often found in aluminum-rich regional metamorphic rocks or pegmatites
About This Crystal
A polished, tumbled stone with a deep denim-blue to violet-blue color. Features a mottled, somewhat grainy appearance with areas of lighter greyish-blue zones and subtle vitreous luster.
Physical Characteristics
Color: Dark blue to grey-blue; Streak: White; Cleavage: One direction (poor in massive form); Fracture: Conchoidal to uneven; Specific Gravity: 3.26–3.41; Fluorescence: Generally inert to weak blue
Optical Properties
Refractive Index: 1.678–1.689; Birefringence: 0.011–0.027; Pleochroism: Strong (blue, violet, red-brown); Optical Phenomenon: None for this specimen
Hardness & Durability
Origin Region
Brazil (Bahia), Madagascar, South Africa, and the United States (Nevada)
Hardness & Durability
Mohs Hardness: 7 to 8.5 (depending on mineral concentration); Toughness: Good; Stability: Very high; suitable for all jewelry types
Care & Maintenance
Clean with warm soapy water and a soft brush; safe for ultrasonic cleaning. Avoid extreme heat and prolonged exposure to harsh acids.
Rarity & Value
Uncommon; worth more when the blue color is intense and evenly distributed. Treatments like dyeing are common in low-grade imitators, but natural specimens are affordable.
Special Characteristics
Strongly pleochroic crystals; when found as inclusions in quartz, it creates a 'Blue Quartz' appearance distinct from sodalite or lapis lazuli due to its higher hardness.
Lore & History
Named after French paleontologist Eugène Dumortier. Historically used as a decorative stone; in modern lore, it is called the 'Stone of Patience' and associated with the Throat and Third Eye chakras.