Amethyst
Quartz var. Amethyst · Semi-Precious Gemstone
Crystal System
Trigonal: typically occurs as hexagonal prisms terminated by rhombohedra; this specimen is a tumbled/polished fragment
Mineral Group
Silicates (Tectosilicate)
Chemical Formula
SiO2 (Silicon Dioxide) with trace impurities of Fe3+ (Iron) and natural irradiation
Formation Process
Found in hydrothermal veins and basaltic geodes. Its purple color results from irradiation of iron impurities within the quartz lattice during formation
About This Crystal
Deep purple, translucent to transparent specimen. This specific piece is a small tumbled stone showing a vitreous (glass-like) luster and slight color zoning
Physical Characteristics
Color: Violet to dark purple. Streak: White. Cleavage: None. Fracture: Conchoidal. Specific Gravity: 2.65. Fluorescence: Usually inert but can show weak green/blue under UV
Optical Properties
Refractive Index: 1.544-1.553. Birefringence: 0.009. Pleochroism: Weak to moderate in shades of purple and reddish-purple. Uniaxial (+)
Hardness & Durability
Origin Region
Brazil, Uruguay, Zambia, Madagascar, and Russia; typically found in volcanic geodes and hydrothermal veins
Hardness & Durability
Mohs Hardness: 7. Toughness: Good. Stable under normal conditions but can fade with extreme heat or prolonged direct sunlight
Care & Maintenance
Clean with warm soapy water. Avoid ultrasonic cleaners if there are fractures. Store away from direct sunlight to prevent color fading and separate from harder stones like Topaz or Sapphire
Rarity & Value
Common. Value factors include color depth ('Siberian' deep purple is most valued) and clarity. Low to moderate price range per carat. Heat treatment is common to produce Citrine
Special Characteristics
Often exhibits color zoning (alternating dark and light purple bands). May contain 'tiger stripe' inclusions or liquid-filled cavities
Lore & History
Historically associated with preventing intoxication (Greek 'amethystos'). Symbolizes wisdom and peace. Traditionally used in royal jewelry and associated with the Crown Chakra