Amethyst
Quartz var. Amethyst (IMA-approved: Quartz) · Semi-Precious Gemstone / Mineral Specimen.
Crystal System
Trigonal/Hexagonal; usually forms as prismatic crystals with six-sided pyramids, but in this specimen, it is polished into a spherical habit.
Mineral Group
Silicates; Tectosilicate subgroup (Framework Silicates).
Chemical Formula
SiO2 (Silicon Dioxide) with trace amounts of Iron (Fe3+) and irradiation-induced color centers.
Formation Process
Found in hydrothermal veins and volcanic cavities (geodes) where silica-rich fluids crystallize at relatively low temperatures.
About This Crystal
A violet to purple variety of quartz. This specimen is a polished sphere showing translucent to nearly opaque areas with internal fractures and lavender-purple color zoning.
Physical Characteristics
Color: Pale violet to deep purple, Streak: White, Cleavage: None, Fracture: Conchoidal, Specific Gravity: 2.65, Tenacity: Brittle. Does not typically fluoresce.
Optical Properties
Refractive Index: 1.544-1.553, Birefringence: 0.009, Pleochroism: Weak to moderate purple/reddish-purple. Doubly refractive.
Hardness & Durability
Origin Region
Major sources include Brazil, Uruguay, Madagascar, and Zambia. Commonly found in basaltic geodes or hydrothermal veins.
Hardness & Durability
Mohs Hardness: 7. Excellent durability for jewelry, though internal fractures (visible in this sphere) can make it susceptible to impacts.
Care & Maintenance
Clean with warm soapy water. Avoid ultrasonic cleaners if internal fractures are present. Keep out of prolonged direct sunlight to prevent color fading.
Rarity & Value
Common. Value is determined by color saturation and clarity; deep 'Siberian' purple is most valued. Often heat-treated to produce Citrine.
Special Characteristics
Displays color zoning (uneven distribution of purple color) and internal veining or 'feathers' (fractures) as seen in this polished sphere.
Lore & History
Ancient Greeks believed it prevented intoxication. Historically associated with royalty and the Third Eye/Crown chakras in modern crystal healing.