Amethyst
Quartz var. Amethyst · Semi-Precious Gemstone / Mineral Specimen
Crystal System
Trigonal; Hexagonal prisms usually ending in rhombohedral terminations; commonly found as druzy clusters or within geodes
Mineral Group
Silicates (Tectosilicate subgroup)
Chemical Formula
SiO2 (Silicon Dioxide) with traces of Iron (Fe3+) and natural irradiation
Formation Process
Hydrothermal formation; originating from silica-rich fluids precipitating in cavities within volcanic rocks (geodes) or veins during low to medium temperature metamorphic processes
About This Crystal
A cluster of small, translucent to transparent purple crystals with a vitreous (glassy) luster. Shows characteristic purple color zoning where the color is most intense at the crystal tips and fades toward the base
Physical Characteristics
Color: Pale lilac to deep royal purple; Streak: White; Cleavage: None (indistinct); Fracture: Conchoidal; Specific Gravity: 2.65; Fluorescence: Usually inert but can show weak green or blue under UV
Optical Properties
Refractive Index: 1.544–1.553; Birefringence: 0.009; Pleochroism: Weak to moderate in shades of purple and reddish-purple; Uniaxial (+)
Hardness & Durability
Origin Region
Notably Brazil (Rio Grande do Sul), Uruguay, Madagascar, Zambia, and Russia; typically forms in volcanic basalt cavities or hydrothermal veins
Hardness & Durability
Mohs Hardness: 7; Toughness: Good; Stability: Stable to most chemicals but sensitive to high heat and prolonged direct sunlight
Care & Maintenance
Clean with warm soapy water and a soft brush; avoid ultrasonic or steam cleaners if inclusions are present; store away from direct sunlight to prevent color fading
Rarity & Value
Common to Uncommon; value is determined by color depth (Siberian purple being most prized), clarity, and size; heat treatment is common to produce Citrine
Special Characteristics
Can exhibit 'tiger stripe' or 'zebra' inclusions (iron staining/growth patterns); often shows color zoning; can be synthesized or irradiated
Lore & History
Derived from Greek 'amethystos' (not intoxicated); historically used to prevent drunkenness. In traditional lore, it is associated with the Third Eye and Crown chakras, believed to promote clarity and calm