Amethyst
Quartz var. Amethyst · Semi-Precious Gemstone
Crystal System
Trigonal; typically occurs as hexagonal prisms terminated by two sets of rhombohedrons, or as massive, druzy, or geode formations.
Mineral Group
Silicates (Tectosilicate subgroup)
Chemical Formula
SiO2 (Silicon Dioxide) with trace amounts of Iron (Fe3+) and natural irradiation
Formation Process
Primarily Hydrothermal; forms from silica-rich solutions in cavities (vugs) within volcanic rocks or sedimentary environments at relatively low temperatures.
About This Crystal
A violet to purple variety of quartz. It features a vitreous (glassy) luster and ranges from transparent to translucent. Color is often zoned and most intense at the crystal tips. This specific specimen appears to be a raw, fractured fragment showing conchoidal texture and internal veining.
Physical Characteristics
Color: Purple/Violet; Streak: White; Cleavage: None; Fracture: Conchoidal (shell-like); Specific Gravity: 2.65; Tenacity: Brittle; Fluorescence: Generally inert, occasionally weak bluish/greenish under UV.
Optical Properties
Refractive Index: 1.544–1.553; Birefringence: 0.009; Pleochroism: Weak to moderate in purple/reddish-purple; Uniaxial (+); No fire or chatoyancy usually present.
Hardness & Durability
Origin Region
Major sources include Brazil (Rio Grande do Sul), Uruguay, Zambia, Madagascar, and Russia. Often found in volcanic geodes or hydrothermal veins.
Hardness & Durability
Mohs Hardness: 7; Toughness: Good; Stability: Stable to most household chemicals but sensitive to extreme heat and prolonged UV exposure.
Care & Maintenance
Clean with warm soapy water and a soft brush. Avoid ultrasonic or steam cleaners if there are many inclusions. Store away from direct sunlight to prevent color fading and separate from harder gems like diamonds.
Rarity & Value
Common; Value depends on 'Siberian' deep purple color with red/blue flashes. Frequently heat-treated to produce Citrine or Green Quartz (Prasiolite). Highly affordable as decorative specimens.
Special Characteristics
Color zoning is common. May contain 'tiger stripe' inclusions or liquid-filled cavities. Notable for its dichroism and potential to change color under high heat.
Lore & History
Historically worn by Ancient Greeks to prevent intoxication (from 'amethystos', meaning 'not intoxicated'). Widely used in royal jewelry and ecclesiastical rings. In modern crystal practices, it is associated with the Third Eye and Crown Chakras, believed to promote calm and clarity.