Clear Quartz
Quartz (Silicon Dioxide) · Semi-Precious Gemstone / Mineral Specimen
Crystal System
Trigonal crystal system with a Hexagonal crystal family; habit is typically prismatic with pyramidal terminations, though this specimen is massive/crystalline.
Mineral Group
Silicates (Tectosilicates)
Chemical Formula
SiO2
Formation Process
Primarily Hydrothermal or Magmatic; forms from silica-rich solutions in veins, cavities, and crustal rocks under a wide range of temperatures and pressures.
About This Crystal
Clear to translucent white crystalline mass with a vitreous to greasy luster. The surface appears irregular and fractured, typical of a 'rough' or 'raw' specimen without defined external crystal faces.
Physical Characteristics
Color: Colorless to white; Streak: White; Cleavage: None/Indistinct; Fracture: Conchoidal; Specific Gravity: 2.65; Fluorescence: Usually inert/none.
Optical Properties
Refractive Index: 1.544-1.553; Birefringence: 0.009; Uniaxial (+); no pleochroism; high transparency allows for internal light scattering.
Hardness & Durability
Origin Region
Globally abundant; notable sources include Brazil (Minas Gerais), Arkansas (USA), Madagascar, and the Alps. Found in pegmatites and hydrothermal veins.
Hardness & Durability
Mohs Hardness: 7; Toughness: Good (brittle but lacks cleavage); very stable under normal conditions and resistant to most chemical weathering.
Care & Maintenance
Wash with warm soapy water; safe for ultrasonic cleaners. Store separately from softer stones like Calcite to avoid scratching them, or from diamonds which can scratch quartz.
Rarity & Value
Common; value is determined by clarity, size, and presence of interesting inclusions. Small rough specimens are very affordable, often used as teaching aids or decorative items.
Special Characteristics
Piezoelectric and pyroelectric properties; this specimen likely shows internal fractures that create small rainbows due to light interference.
Lore & History
Historically used for tool-making and optics (lenses). Ancient Greeks believed it was 'krystallos' (permanent ice). Culturally associated with clarity and amplifications in traditional belief systems.