Druzy Quartz (Amethyst/Smoky Quartz Geode)
Quartz (Silicon Dioxide) var. Druzy Amethyst with Goethite inclusions · Mineral Specimen / Semi-Precious Gemstone
Crystal System
Trigonal system; habit is typically druzy (carpet of tiny crystals) within a geode or vug
Mineral Group
Silicates (Tectosilicate subgroup)
Chemical Formula
SiO2 (Trace elements: Fe3+ for color, inclusions often FeO(OH))
Formation Process
Hydrothermal/Igneous: Forms when silica-rich fluids permeate cavities in volcanic basalt or sedimentary rock at low temperatures
About This Crystal
A cluster of tiny, sparkling crystals (druse) with colors ranging from pale violet to brownish-pink and grey. Features a vitreous luster and various levels of transparency from translucent to opaque with dark mineral inclusions.
Physical Characteristics
Color: Lavender, mauve, and earthy brown; Streak: White; Cleavage: None; Fracture: Conchoidal (macroscopic); Specific Gravity: 2.65; Fluorescence: Generally inert to weak green/blue
Optical Properties
Refractive Index: 1.544-1.553; Birefringence: 0.009 (uniaxial positive); Optical Phenomenon: Scintillation (sparkle) from multiple tiny crystal faces
Hardness & Durability
Origin Region
Rio Grande do Sul, Brazil; Artigas, Uruguay; typically found in volcanic basalt flows
Hardness & Durability
Mohs Hardness: 7; Toughness: Weak (due to brittle crystalline structure); Stability: Stable, though extreme heat may cause color fading
Care & Maintenance
Clean with warm soapy water and a soft brush; avoid ultrasonic cleaners which may loosen small crystals; store away from direct sunlight to prevent fading
Rarity & Value
Common; value determined by color saturation, sparkle intensity, and specimen size; price range $10 - $500 for decorative pieces
Special Characteristics
Sparkling druse effect; dark 'pepper' inclusions likely being Goethite or Hematite; macro-geode structure
Lore & History
Historically used by Greeks to prevent intoxication; traditionally associated with the Crown Chakra, believed to promote calm, clarity, and spiritual protection