Amethyst
Quartz variety Amethyst · Semi-Precious Gemstone / Mineral specimen
Crystal System
Trigonal; typically occurs as hexagonal prisms terminated by rhombohedra, often found in druzy clusters, geodes, and massive forms.
Mineral Group
Silicates (Subgroup: Tectosilicates)
Chemical Formula
SiO2 (Silicon Dioxide) with traces of iron (Fe3+) and natural irradiation
Formation Process
Hydrothermal; forms from silica-rich fluids in gas cavities (vesicles) of volcanic rocks or in hydrothermal veins at low to moderate temperatures.
About This Crystal
Transparent to translucent purple quartz. Displays colors ranging from pale lavender to deep violet. The image shows druzy clusters (bottom left and center) consisting of many small crystal points, and tumbled/polished stones with vitreous luster and visible internal fractures or color zoning.
Physical Characteristics
Color: Violet to purple; Streak: White; Cleavage: None (indistinct); Fracture: Conchoidal; Specific Gravity: 2.65; Fluorescence: Usually inert but can show weak green or blue under UV light.
Optical Properties
Refractive Index: 1.544–1.553; Birefringence: 0.009; Optical Character: Uniaxial (+); Pleochroism: Weak to moderate in shades of purple and reddish-purple.
Hardness & Durability
Origin Region
Brazil (Rio Grande do Sul), Uruguay (Artigas), Madagascar, Zambia, and Russia; typically forms in volcanic cavities and hydrothermal veins.
Hardness & Durability
Mohs Hardness: 7; Toughness: Good; Stability: Generally stable but can fade with prolonged exposure to high heat or direct sunlight.
Care & Maintenance
Clean with warm soapy water and a soft brush; avoid ultrasonic cleaners and steam cleaning; store out of direct sunlight to prevent color fading.
Rarity & Value
Common; Value is determined by color intensity (deep Siberian purple is highest), clarity, and size. Most commercial amethyst is heat-treated to enhance color or produce Citrine.
Special Characteristics
Color zoning (stripes of darker and lighter purple), 'tiger stripe' inclusions, and occasional phantom crystal growth within the points.
Lore & History
Historically used in ancient Greece to prevent intoxication (derived from 'amethystos', meaning 'not intoxicated'). Traditionally associated with the Third Eye and Crown Chakras; believed to promote calm, clarity, and spiritual protection.