Clear Quartz
Quartz var. Rock Crystal · Semi-Precious Gemstone / Mineral Specimen
Crystal System
Trigonal crystal system; habit is typically six-sided prisms terminating with six-sided pyramids
Mineral Group
Silicates; Tectosilicate subgroup
Chemical Formula
SiO2
Formation Process
Primarily Hydrothermal in veins and pegmatites; also occurs in Igneous and Metamorphic environments
About This Crystal
Colorless and transparent mineral with a vitreous (glassy) luster. Shows conchoidal fracture and may contain internal fractures or inclusions
Physical Characteristics
Colorless; streak is white; no cleavage; conchoidal fracture; specific gravity 2.65; piezoelectric; usually non-fluorescent
Optical Properties
Refractive index 1.544-1.553; birefringence 0.009; uniaxial positive; no pleochroism; low dispersion
Hardness & Durability
Origin Region
Global; notable sources include Brazil (Minas Gerais), Arkansas (USA), Madagascar, and the Alps
Hardness & Durability
Mohs hardness 7; high toughness; very stable against heat and chemicals; excellent for all jewelry types
Care & Maintenance
Wash with warm soapy water; safe for ultrasonic cleaners; avoid hydrofluoric acid; store away from harder stones
Rarity & Value
Common; value depends on clarity and size, with water-clear specimens and specific inclusions commanding higher prices
Special Characteristics
Piezoelectric and pyroelectric properties; can feature phantom inclusions or rutilation; no natural play of color
Lore & History
Historically used for tools, lenses, and crystal balls; traditionally associated with the Crown Chakra and 'master healing' in lore