Amethyst
Quartz var. Amethyst · Semi-Precious Gemstone / Mineral Specimen
Crystal System
Trigonal; typical habit in this specimen is a druzy cluster of small prismatic crystals terminating in rhombohedral faces.
Mineral Group
Silicates (Tectosilicate subgroup)
Chemical Formula
SiO2 (Silicon Dioxide) with trace amounts of Fe3+ (iron) and natural irradiation
Formation Process
Hydrothermal; formed from silica-rich fluids precipitating in gas cavities (vesicles) of volcanic rock at relatively low temperatures.
About This Crystal
A heart-shaped druzy cluster featuring translucent to transparent purple crystals. It exhibits a vitreous (glassy) luster and visible pyramidal crystal terminations. The color presents as a soft violet to lilac hue with internal crystalline fractures.
Physical Characteristics
Color: Purple/Violet; Streak: White; Cleavage: None; Fracture: Conchoidal; Specific Gravity: 2.65; Fluorescence: Usually inert but can show weak green or blue under UV.
Optical Properties
Uniaxial positive; Refractive Index: 1.544–1.553; Birefringence: 0.009; Pleochroism: Weak to moderate purple/reddish-purple.
Hardness & Durability
Origin Region
Notable sources include Uruguay and Brazil (Rio Grande do Sul). Commonly found in volcanic basalt geodes.
Hardness & Durability
Mohs Hardness: 7; Toughness: Fair to Good; highly durable for jewelry but brittle due to crystalline structure.
Care & Maintenance
Care: Clean with warm soapy water. Avoid ultrasonic cleaners if the specimen has significant inclusions. Protect from prolonged direct sunlight to prevent color fading.
Rarity & Value
Common; Value is determined by color depth (deep 'Siberian' purple is most prized) and clarity. This lilac druzy specimen is affordable and popular for decor.
Special Characteristics
The specimen features a 'druse' texture where tiny crystals coat a host rock surface, often showing color zoning within individual crystals.
Lore & History
Historically used by Ancient Greeks to prevent intoxication (from 'amethystos', meaning 'not drunken'). In metaphysical traditions, it is associated with the Crown Chakra, peace, and spiritual protection.