Dumortierite Quartz
Quartz var. Dumortierite Inclusions · Semi-Precious Gemstone / Decorative Stone
Crystal System
Trigonal; typically tumbled into a rounded pebble habit in this specimen.
Mineral Group
Silicates (Tectosilicate subgroup)
Chemical Formula
SiO2 with inclusions of Al7BO3(SiO4)3O3
Formation Process
Metamorphic and pegmatitic processes where aluminum-rich borosilicate minerals like dumortierite crystallize within or become trapped inside host quartz during growth.
About This Crystal
A tumbled, smooth, pebble-shaped specimen displaying a rich, deep royal blue to indigo color. It features translucent to opaque areas with characteristic lighter blue and white cloud-like internal inclusions and mottling. The surface exhibits a high-polish vitreous luster.
Physical Characteristics
Color ranges from deep blue to indigo-violet with white mottled patches; white streak; no distinct cleavage; conchoidal fracture; specific gravity around 2.65; brittle tenacity; displays vitreous luster.
Optical Properties
Singly or doubly refractive depending on the quartz matrix (uniaxial positive); refractive index around 1.544-1.553; typically non-pleochroic in the mass aggregate form, exhibiting a solid vitreous to sub-vitreous sheen.
Hardness & Durability
Origin Region
Notable sources include Madagascar, Namibia, Brazil, and the USA. Forms in metamorphic and pegmatitic environments.
Hardness & Durability
Mohs hardness of 7 for the host quartz matrix, making it very durable and suitable for everyday jewelry wear, though dumortierite inclusions themselves range from 7 to 8.5.
Care & Maintenance
Clean with warm soapy water and a soft brush; avoid harsh chemicals, ultrasonic cleaners, and prolonged exposure to direct, intense sunlight to maintain polish and color.
Rarity & Value
Uncommon to Rare depending on the intensity and uniformity of the blue coloration; high-grade saturated blue stones are sought after by collectors and jewelers, with affordable pricing for tumbled stones.
Special Characteristics
Features striking fibrous or cloud-like internal blue inclusions of dumortierite mineral dispersed within a clear-to-milky quartz host, creating a denim-blue or starry night appearance.
Lore & History
Often referred to as the Stone of Patience and Order, it is traditionally associated with the third eye and throat chakras, believed by practitioners to enhance mental discipline, organization, and clear communication, though these are cultural lore rather than scientifically proven claims.