Clear Quartz (Rock Crystal)
Quartz (Alpha Quartz) · Semi-Precious Gemstone / Mineral Specimen
Crystal System
Trigonal (Hexagonal Trapezohedral). Habit: Hexagonal prisms terminated by rhombohedrons; also massive, as pictured.
Mineral Group
Silicates (Tectosilicate)
Chemical Formula
SiO2
Formation Process
Primarily Hydrothermal or Igneous. Formed from silica-rich solutions in veins and cavities under wide-ranging temperature and pressure conditions.
About This Crystal
Colorless, transparent to translucent specimen with a vitreous (glassy) luster. Shows typical conchoidal fracture patterns with no visible external crystal faces, suggesting it is a broken fragment of a larger mass.
Physical Characteristics
Color: Colorless; Streak: White; Cleavage: None (indistinct); Fracture: Conchoidal; Specific Gravity: 2.65; Fluorescence: Usually inert; Piezoelectric properties.
Optical Properties
Uniaxial positive; Refractive Index: 1.544-1.553; Birefringence: 0.009; No pleochroism; Doubly refractive.
Hardness & Durability
Origin Region
Globally abundant; notable sources include Brazil (Minas Gerais), Arkansas (USA), and Madagascar. Found in pegmatites and hydrothermal veins.
Hardness & Durability
Mohs Hardness: 7. Toughness: Good. Highly stable for jewelry; resistant to most household chemicals except hydrofluoric acid.
Care & Maintenance
Clean with warm soapy water and a soft brush. Ultrasonic and steam cleaning are generally safe unless it contains significant internal fractures (veils). Store away from harder stones like Sapphire or Diamond.
Rarity & Value
Very common. Value is determined by clarity, size, and lack of internal fractures. Common treatments include irradiation or coating (Aura Quartz), though this specimen appears natural.
Special Characteristics
Displays conchoidal fracture surfaces. May exhibit piezoelectricity (generates electric charge under mechanical stress) and contains internal veils or 'feathers'.
Lore & History
Historically known as 'Krystallos' (frozen ice) by Ancient Greeks. Central to many cultures for tools and ornamental use. In modern lore, it is considered a 'Master Healer' associated with the Crown Chakra and amplification of energy.