Clear Quartz (Rock Crystal)
Quartz (Silicon Dioxide) · Semi-Precious Gemstone / Mineral Specimen
Crystal System
Trigonal; commonly occurs as hexagonal prisms terminated by rhombohedra. These specimens are small, tumbled chips (alluvial or mechanically processed shards).
Mineral Group
Silicates (Tectosilicate)
Chemical Formula
SiO2
Formation Process
Primarily Magmatic and Hydrothermal. Forms as silica-rich fluids cool in crustal cavities, typically under a wide range of temperatures and pressures.
About This Crystal
Small, colorless, transparent to translucent tumbled chips. Exhibits a vitreous (glassy) luster with no visible inclusions in most fragments.
Physical Characteristics
Color: Colorless; Streak: White; Cleavage: Poor/Indistinct; Fracture: Conchoidal; Specific Gravity: 2.65; Fluorescence: Usually inert but can show weak green/yellow under UV if certain trace elements are present.
Optical Properties
Refractive Index: 1.544-1.553; Birefringence: 0.009; Optical Character: Uniaxial positive; Dispersion: 0.013. Doubly refractive.
Hardness & Durability
Origin Region
Worldwide; notably Brazil (Minas Gerais), Arkansas (USA), Madagascar, and the Alps. Occurs in pegmatites and hydrothermal veins.
Hardness & Durability
Mohs Hardness: 7; Toughness: Good; Stability: Very stable, resistant to most acids and heat, making it excellent for all jewelry types.
Care & Maintenance
Safe to clean with warm soapy water, ultrasonic cleaners, or steam. Store separately to avoid scratching softer stones. Avoid hydrofluoric acid.
Rarity & Value
Common; Very affordable in this chip/tumbled form. Value increases with size, clarity, and specific crystal habits (e.g., faden, phantom).
Special Characteristics
Piezoelectric and pyroelectric properties; can hold electrical charge under pressure or heat changes. These chips show standard vitreous reflection.
Lore & History
Historically used in 'scrying' or crystal balls. In metaphysical traditions, it is known as the 'Master Healer' and is associated with the Crown Chakra and the amplification of energy.