Amethyst
Quartz variety Amethyst · Semi-Precious Gemstone / Jewelry Material
Crystal System
Trigonal; typically occurs in hexagonal prismatic crystals terminated by rhombohedra; those in the image are tumbled beads.
Mineral Group
Silicates (Tectosilicate subgroup / Quartz group)
Chemical Formula
SiO2 (Silicon Dioxide) with traces of Iron (Fe4+) and natural irradiation
Formation Process
Hydrothermal; typically forms in the cavities (geodes) of igneous rocks or in hydrothermal veins at low to moderate temperatures.
About This Crystal
Transparent to translucent purple quartz. These tumbled beads show a light to medium violet hue, vitreous luster, and smooth polished surfaces with some internal veining and faint color zoning.
Physical Characteristics
Color: light purple; Streak: White; Cleavage: None; Fracture: Conchoidal; Specific Gravity: 2.65; Fluorescence: Usually inert but can show weak greenish-blue under UV.
Optical Properties
Refractive Index: 1.544–1.553; Birefringence: 0.009; Optical Character: Uniaxial positive; Dichroism: Weak to moderate purple/reddish-purple.
Hardness & Durability
Origin Region
Major sources include Brazil, Uruguay, Zambia, Madagascar, and Russia (Ural Mountains).
Hardness & Durability
Mohs Hardness: 7; Toughness: Good; Stability: Stable but can fade with prolonged exposure to high heat or intense UV light.
Care & Maintenance
Safe to clean with warm soapy water. Avoid ultrasonic cleaners or steam cleaners if there are many inclusions. Store away from direct sunlight to prevent color fading.
Rarity & Value
Common; Value is determined by color depth (vivid purple is best), clarity, and cut. Light-colored beads like these are widely available and affordable.
Special Characteristics
Visible color zoning (geometric distribution of color) and internal 'tiger-stripe' inclusions are common in natural Amethyst.
Lore & History
Historically worn by ancient Greeks to prevent intoxication (as the name 'amethystos' suggests). Associated with the Crown Chakra, peace, and spiritual protection in traditional lore.