Amethyst
Quartz var. Amethyst · Semi-Precious Gemstone
Crystal System
Trigonal system; typically occurs as six-sided prismatic crystals terminating in rhombohedral faces, or as druzy carpets within geodes.
Mineral Group
Silicates (Tectosilicate subgroup)
Chemical Formula
SiO2 (Silicon Dioxide) with traces of Iron (Fe3+)
Formation Process
Hydrothermal formation where silica-rich fluids deposit in cavities (vugs/geodes) within igneous or metamorphic rocks at relatively low temperatures.
About This Crystal
A violet to purple variety of quartz. Exhibits a vitreous luster, ranging from transparent to translucent. The specimens in the image show varied habits: raw druzy clusters, polished heart shapes with chevron banding, and a tumbled orb.
Physical Characteristics
Color: Pale lilac to deep purple; Streak: White; Cleavage: None; Fracture: Conchoidal; Specific Gravity: 2.65; Fluorescence: Generally inert, occasionally weak blue/green under UV.
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
Brazil (Rio Grande do Sul), Uruguay (Artigas), Madagascar, Zambia, and Russia; often found in volcanic basalt cavities.
Hardness & Durability
Mohs Hardness: 7; Toughness: Good; highly durable for jewelry use but can be chipped by sharp impacts.
Care & Maintenance
Clean with warm soapy water and a soft brush; avoid ultrasonic cleaners if there are many inclusions. Protect from prolonged direct sunlight to prevent color fading.
Rarity & Value
Relatively common; value is determined by deep 'Siberian' purple saturation, clarity, and lack of visible zoning. Larger druzy pieces and clean faceted stones are more valuable.
Special Characteristics
Color-zoning is common; 'Chevron' amethyst (seen in the small hearts) features V-shaped white quartz banding; may contain hematite or goethite inclusions.
Lore & History
Historically used by Ancient Greeks to prevent intoxication ('amethystos' means 'not drunk'). Symbolizes peace, sobriety, and spiritual protection; traditionally associated with the Third Eye and Crown chakras.