Clear Quartz (Rock Crystal)
Quartz (Alpha-Quartz) · Semi-Precious Gemstone / Mineral Specimen
Crystal System
Trigonal; typically prismatic, often found as druzy or macrocrystalline clusters in geodes/cavities
Mineral Group
Silicates (Tectosilicates)
Chemical Formula
SiO2
Formation Process
Hydrothermal; forms from silica-rich solutions in rock cavities and veins at various temperatures
About This Crystal
Transparent to translucent white crystals with a vitreous (glassy) luster, appearing as a crystalline pocket or druse within a host rock matrix
Physical Characteristics
Colorless/white; white streak; no true cleavage; conchoidal fracture; 2.65 specific gravity; occasionally fluorescent
Optical Properties
Uniaxial positive; refractive index 1.544-1.553; low birefringence (0.009); no pleochroism
Hardness & Durability
Origin Region
Worldwide; notable sources include Brazil, Arkansas (USA), and Madagascar; commonly found in hydrothermal veins
Hardness & Durability
Mohs hardness 7; very durable and stable for most jewelry and display purposes
Care & Maintenance
Wash with warm soapy water; safe for ultrasonic cleaning; stable in sunlight and most household chemicals
Rarity & Value
Very common; value is determined by clarity, crystal size, and the aesthetics of the matrix/specimen
Special Characteristics
Piezoelectric and pyroelectric; may exhibit phantom growth lines or internal fractures creating slight rainbows
Lore & History
Historically used for tools and rituals; symbolically associated with clarity, amplification of energy, and the crown chakra