Dumortierite in Quartz
Dumortierite (Al7BO3(SiO4)3O3) within Quartz · Collector Mineral / Semi-Precious Gemstone
Crystal System
Orthorhombic (Dumortierite) and Trigonal (Quartz); often found in massive or fibrous habits within the matrix.
Mineral Group
Silicates (Nesosilicates for Dumortierite; Tectosilicates for Quartz)
Chemical Formula
Al7BO3(SiO4)3O3 (Dumortierite) / SiO2 (Quartz)
Formation Process
Metamorphic or pegmatitic; forms through high-temperature regional metamorphism or in boron-rich granitic pegmatites.
About This Crystal
The specimen shows a violet to reddish-purple inclusion within a grayish, dull matrix. The internal mineral appears translucent to opaque with a waxy to vitreous luster, embedded in a granular host rock.
Physical Characteristics
Color: Violet, blue, or reddish-brown; Streak: White; Cleavage: Good on {100}; Fracture: Fibrous to conchoidal; Specific Gravity: 3.21–3.41; Fluorescence: Often none, occasionally blue.
Optical Properties
Refractive Index: 1.670–1.689; Birefringence: 0.011–0.020; Pleochroism: Strong (deep blue/violet to colorless/yellow); Biaxial negative.
Hardness & Durability
Origin Region
Notable sources include Brazil, Madagascar, South Africa, and the United States (Nevada). Found often in aluminum-rich regional metamorphic rocks.
Hardness & Durability
Mohs Hardness: 7 to 8.5; Toughness: Good to excellent in massive form; Stability: Very stable against heat and chemicals.
Care & Maintenance
Safe to clean with warm soapy water. Resistant to most chemicals, but should be stored away from harder stones like Sapphire or Diamond to prevent scratching.
Rarity & Value
Uncommon in high-quality crystalline form; massive blue/violet material is fairly available. Value factors include color intensity and clarity of the host quartz.
Special Characteristics
Displays strong pleochroism and occasionally found as 'Blue Quartz' where microscopic dumortierite inclusions color the entire crystal.
Lore & History
Discovered in 1881 and named after paleontologist Eugène Dumortier. Traditionally associated with mental discipline, patience, and the Throat and Third Eye chakras.