Dumortierite Quartz
Quartz var. Dumortierite Quartz · Mineral Specimen and Semi-Precious Stone
Crystal System
Trigonal, massive habit with fibrous or acicular inclusions
Mineral Group
Silicates, specifically Tectosilicates
Chemical Formula
SiO2 with inclusions of AlBSi3O9(O,OH)3
Formation Process
Hydrothermal and metamorphic processes where aluminum borosilicate minerals form alongside crystallizing quartz
About This Crystal
A tumbled or naturally weathered white quartz pebble featuring distinctive patches of dark blue to grayish-blue dumortierite inclusions beneath the surface, showing a translucent to opaque appearance with a vitreous to waxy luster.
Physical Characteristics
White to greyish body color with blue patches, white streak, conchoidal fracture, specific gravity around 2.65, brittle tenacity, and no notable cleavage for the quartz host.
Optical Properties
Singly or doubly refractive with a refractive index of approximately 1.544 to 1.553, uniaxial positive optical character, and no strong pleochroism visible in the host quartz.
Hardness & Durability
Origin Region
Brazil, Madagascar, Namibia, and the USA; typically found in pegmatites and metamorphic rocks
Hardness & Durability
Mohs hardness of 7 for the quartz host, making it durable for daily wear, though the inclusion areas can sometimes create localized weaknesses.
Care & Maintenance
Clean with warm soapy water using a soft brush; avoid harsh chemicals and prolonged direct sunlight if color preservation of sensitive matrix areas is desired.
Rarity & Value
Uncommon to rare depending on the concentration and vividness of the blue inclusions; valued primarily by collectors and lapidary artists.
Special Characteristics
Features distinct fibrous or patchy blue mineral inclusions (dumortierite) locked inside a host quartz matrix.
Lore & History
Often associated with mental discipline, focus, and emotional calmness in modern crystal lore, though these are strictly traditional beliefs and not scientifically proven.