Amethyst
Quartz var. Amethyst · Semi-Precious Gemstone
Crystal System
Trigonal system; commonly occurs as hexagonal prisms terminated by rhombohedra. This specimen is a tumbled or water-worn crystal fragment showing uneven surfaces.
Mineral Group
Silicates (Tectosilicate)
Chemical Formula
SiO2 with trace amounts of Iron (Fe3+)
Formation Process
Found in hydrothermal veins and basaltic geodes; forms from silica-rich water at low to moderate temperatures, where iron impurities are irradiated by surrounding rock.
About This Crystal
Transparent to translucent purple variety of quartz. This specific specimen exhibits a medium-to-dark violet saturation with visible internal fractures and possible white quartz banding (chevron) common in found fragments.
Physical Characteristics
Color: Violet to purple; Streak: White; Luster: Vitreous; Fracture: Conchoidal; Specific Gravity: 2.65; Fluorescence: Usually inert but can show weak greenish-blue under UV light.
Optical Properties
Refractive Index: 1.544–1.553; Birefringence: 0.009; Optical Character: Uniaxial positive; Pleochroism: Weak to moderate purple and reddish-purple.
Hardness & Durability
Origin Region
Brazil, Uruguay, Zambia, Madagascar, and Russia. Found in volcanic geodes or hydrothermal veins.
Hardness & Durability
Mohs Hardness: 7; Toughness: Good (no cleavage); Stable for jewelry use but sensitive to extreme heat.
Care & Maintenance
Avoid prolonged exposure to direct sunlight as colors may fade. Clean with warm soapy water and a soft brush; ultrasonic cleaners are generally safe unless the stone has heavy inclusions/fractures.
Rarity & Value
Common; value is determined by color intensity (deep 'Siberian' purple is most valuable) and clarity. Large quantities are sourced from South American geodes.
Special Characteristics
Dichroism; color zoning (alternating dark and light purple layers); sometimes contains goethite or cacoxenite inclusions; phantom growth lines.
Lore & History
Historically worn by ancient Greeks to prevent intoxication (from 'amethystos', meaning 'not drunken'). Traditionally associated with the Third Eye and Crown chakras, believed to promote calm, balance, and spiritual clarity.