Amethyst
Quartz var. Amethyst · Semi-Precious Gemstone / Mineral Specimen
Crystal System
Trigonal; typically occurs as hexagonal prisms terminated by two sets of rhombohedra. These tumbled chips show an allotriomorphic to subhedral habit.
Mineral Group
Silicates (Tectosilicate subgroup)
Chemical Formula
SiO2 (Silicon Dioxide) with trace impurities of Iron (Fe3+) and natural irradiation
Formation Process
Hydrothermal; formed from silica-rich solutions in cavities (geodes) of volcanic rocks or in metamorphic veins at low to moderate temperatures.
About This Crystal
Small, tumbled chips ranging from pale lilac to medium purple. The specimens are transparent to translucent with a vitreous (glass-like) luster and show typical conchoidal fracture edges.
Physical Characteristics
Color: Lavender to purple; Streak: White; Cleavage: None; Fracture: Conchoidal; Specific Gravity: 2.65; Fluorescence: Usually inert but may show weak greenish or reddish tones under UV.
Optical Properties
Refractive Index: 1.544–1.553; Birefringence: 0.009; Optical Character: Uniaxial positive; Weak pleochroism in shades of purple.
Hardness & Durability
Origin Region
Brazil, Uruguay, Zambia, Madagascar, and South Korea; typically found in volcanic geodes or hydrothermal veins.
Hardness & Durability
Mohs Hardness: 7; Toughness: Good; Stability: Stable but sensitive to prolonged high heat and intense direct sunlight which can cause fading.
Care & Maintenance
Clean with warm soapy water and a soft brush; avoid ultrasonic cleaners if fractures are present; store away from direct sunlight to prevent color loss.
Rarity & Value
Common; value is determined by color intensity (deep 'Siberian' purple being highest), clarity, and size. Tumbled chips are very affordable and widely available.
Special Characteristics
Color zoning is common in larger crystals; these chips may contain minor inclusions of goethite or fluid-filled negative crystals (phantoms).
Lore & History
Historically worn by ancient Greeks to prevent intoxication; associated with royalty and the Crown Chakra. Symbolizes peace, sobriety, and spiritual protection in traditional lore.