Amethyst
Quartz var. Amethyst · Semi-Precious Gemstone
Crystal System
Trigonal; typically occurs as hexagonal prisms terminated by two sets of rhombohedrons, though this specimen is a tumbled/polished mass.
Mineral Group
Silicates (Tectosilicate subgroup)
Chemical Formula
SiO2 (Silicon Dioxide) with trace impurities of Iron (Fe3+) and natural irradiation
Formation Process
Hydrothermal; forms from silica-rich solutions in cavities (geodes) of volcanic rocks or in hydrothermal veins at relatively low temperatures.
About This Crystal
A small, tumbled pebble roughly 1cm in width. It exhibits a deep purple to violet color with some internal zoning and cloudy white inclusions. The luster is vitreous (glass-like) and it ranges from translucent to transparent in areas.
Physical Characteristics
Color: Violet to purple; Streak: White; Cleavage: None; Fracture: Conchoidal; Specific Gravity: 2.65; Tenacity: Brittle; Fluorescence: Generally inert, occasionally weak greenish-blue under UV.
Optical Properties
Refractive Index: 1.544–1.553; Birefringence: 0.009; Optical Character: Uniaxial positive; Weak pleochroism in shades of purple and reddish-purple.
Hardness & Durability
Origin Region
Major sources include Brazil (Rio Grande do Sul), Uruguay, Madagascar, and Zambia. Commonly found in basaltic geodes or hydrothermal veins.
Hardness & Durability
Mohs Hardness: 7; Toughness: Good; Stability: Stable but can fade with prolonged exposure to high heat or intense sunlight.
Care & Maintenance
Clean with warm soapy water and a soft brush. Avoid ultrasonic cleaners if there are heavy inclusions. Store away from direct sunlight to prevent color fading and separate from harder stones like sapphire or diamond.
Rarity & Value
Common; value is determined by color depth (saturated 'Siberian' purple is most prized), clarity, and size. Heat treatment of low-grade amethyst to create citrine is common.
Special Characteristics
Color zoning is common, often showing stripes of darker and lighter purple. This specimen shows typical 'tiger stripes' or chevron-like internal inclusions common in quartz.
Lore & History
Ancient Greeks believed it prevented intoxication (the name comes from 'amethystos', meaning 'not drunk'). Historically a stone of royalty. In metaphysical traditions, it is associated with the Crown Chakra and believed to promote calm, clarity, and protection.