Amethyst
Quartz var. Amethyst · Semi-Precious Gemstone
Crystal System
Trigonal; typically occurs as six-sided prismatic crystals terminating in pyramids, or in massive/drusy habits.
Mineral Group
Silicates (Tectosilicate)
Chemical Formula
SiO2 (Silicon Dioxide) with trace amounts of Iron (Fe3+)
Formation Process
Hydrothermal; forms in silica-rich solutions at low to moderate temperatures, often within gas cavities (geodes) of volcanic rocks.
About This Crystal
A violet to purple variety of quartz, this specimen appears as a rough, translucent to opaque fragment with a vitreous to earthy luster and uneven surface texture.
Physical Characteristics
Color: Purple/Violet; Streak: White; Cleavage: None; Fracture: Conchoidal to uneven; 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; Pleochroism: Weak to moderate in shades of purple; Uniaxial (+).
Hardness & Durability
Origin Region
Brazil, Uruguay, Madagascar, Zambia, and Russia; typically found in volcanic geodes and hydrothermal veins.
Hardness & Durability
Mohs Hardness: 7; Toughness: Good; Excellent wearability for all jewelry types.
Care & Maintenance
Clean with warm soapy water; avoid prolonged exposure to direct sunlight as colors may fade; avoid steam cleaning and sudden temperature changes.
Rarity & Value
Common; Value is determined by color saturation (deep 'Siberian' purple is highest), clarity, and size. Most common treatment is heat treatment to produce Citrine.
Special Characteristics
Color zoning is frequently present; may contain 'tiger stripe' inclusions or liquid/gas-filled negative crystals.
Lore & History
Historically used by Ancient Greeks to prevent intoxication ('a-methystos'). In crystal healing, it is associated with the Third Eye and Crown chakras, believed to promote calm, clarity, and spiritual protection.