Amethyst (Tumbled Stone)
Quartz var. Amethyst · Semi-Precious Gemstone
Crystal System
Trigonal; this specific specimen is in a 'tumbled' habit, meaning its original hexagonal prismatic shape has been mechanically smoothed into an irregular rounded form.
Mineral Group
Silicates (Tectosilicate)
Chemical Formula
SiO2 (Silicon Dioxide) with trace amounts of Iron (Fe3+) and natural irradiation
Formation Process
Hydrothermal formation within volcanic rock cavities (geodes) or pegmatites where silica-rich fluids crystallize at low to moderate temperatures.
About This Crystal
A deep purple, rounded tumbled stone. It exhibits a vitreous (glassy) luster and appears translucent to nearly opaque due to the depth of color saturation. No visible inclusions are apparent in this lighting, but it shows typical smooth, polished surface texture.
Physical Characteristics
Color: Dark violet to 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 shades of purple and reddish-purple; Optical character: Uniaxial positive.
Hardness & Durability
Origin Region
Brazil, Uruguay, Zambia, Madagascar, and Russia. Often found in volcanic geodes and hydrothermal cavities.
Hardness & Durability
Mohs Hardness: 7; Toughness: Good (no cleavage); highly durable and suitable for all types of jewelry and daily handling.
Care & Maintenance
Clean with warm soapy water and a soft brush. Avoid prolonged exposure to direct sunlight as UV radiation can cause the purple color to fade over time. Avoid harsh chemicals and sudden temperature changes.
Rarity & Value
Common; value depends on color saturation (deeper purple is more valuable) and clarity. Tumbled stones like this are very affordable, typically ranging from $1 to $5 depending on size.
Special Characteristics
Color is produced by interstitial iron impurities and natural irradiation. Tumbled versions show a smooth, glossy surface rather than the natural crystal faces.
Lore & History
Historically used by ancient Greeks to prevent intoxication (the name 'amethystos' means 'not drunken'). It has long been associated with royalty and spiritual protection. In modern crystal lore, it is linked to the Crown Chakra and believed to promote calmness and intuition.