Amethyst
Quartz var. Amethyst · Semi-Precious Gemstone
Crystal System
Trigonal; typically occurs as hexagonal prisms terminated by two sets of rhombohedra; this specimen is a polished heart habit.
Mineral Group
Silicates (Tectosilicate subgroup)
Chemical Formula
SiO2 (Silicon Dioxide) with traces of Iron (Fe4+) and natural irradiation
Formation Process
Hydrothermal; forms from silica-rich solutions in cavities of igneous rocks at relatively low temperatures (50-250°C).
About This Crystal
A polished, heart-shaped stone displaying a deep violet to purple hue. It exhibits high transparency and a vitreous (glassy) luster with a smooth, reflective surface.
Physical Characteristics
Color: Violet/Purple; Streak: White; Cleavage: None; Fracture: Conchoidal; 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 purple and reddish-purple; Uniaxial (+).
Hardness & Durability
Origin Region
Major sources include Brazil, Uruguay, Madagascar, Zambia, and Russia; forms typically in volcanic cavities (geodes) or hydrothermal veins.
Hardness & Durability
Mohs Hardness: 7; Toughness: Good; Stability: Good, though long-term exposure to intense sunlight may cause color fading.
Care & Maintenance
Clean with warm soapy water; safe for ultrasonic cleaners unless heavily included. Avoid prolonged direct sunlight and high heat. Store separately from diamonds or sapphires to prevent scratching.
Rarity & Value
Common; Value determined by depth of color (deep Siberian purple is highest), clarity, and cut. Higher quality stones are often heat-treated to improve color or clarity.
Special Characteristics
Color zoning is common in natural specimens; may display faint internal veining or "tiger stripe" inclusions under magnification.
Lore & History
Historically used in Ancient Greece to prevent intoxication; associated with the Crown Chakra in modern tradition. Symbolizes peace, protection, and spiritual clarity.