Amethyst
Quartz var. Amethyst · Semi-Precious Gemstone / Mineral Specimen
Crystal System
Trigonal; typically occurs as six-sided prisms ending in six-sided pyramids; often found in geodes, druzy clusters, or massive forms
Mineral Group
Silicates; Tectosilicate subgroup (Quartz group)
Chemical Formula
SiO2 (Silicon Dioxide) with trace amounts of Iron (Fe3+) and irradiation
Formation Process
Hydrothermal formation within volcanic rock cavities (geodes) or pegmatites; color results from irradiation of trivalent iron impurities
About This Crystal
A violet to purple variety of quartz. This specific specimen shows color zoning with a concentrated purple tip and a translucent to transparent base. It exhibits a vitreous luster with internal fractures and cloudy inclusions.
Physical Characteristics
Color: Pale lilac to deep purple; Streak: White; Cleavage: None; Fracture: Conchoidal; Specific Gravity: 2.65; Fluorescence: Generally inert, but some may show weak greenish or reddish glow under UV.
Optical Properties
Refractive Index: 1.544–1.553; Birefringence: 0.009; Weak pleochroism in purple/red-purple; Uniaxial positive; No significant dispersion.
Hardness & Durability
Origin Region
Brazil, Uruguay, Zambia, Madagascar, and Russia; typically found in volcanic geodes or hydrothermal veins
Hardness & Durability
Mohs Hardness: 7; Toughness: Good; Highly durable for jewelry, though can be brittle relative to harder gems like sapphire.
Care & Maintenance
Clean with warm soapy water; avoid ultrasonic or steam cleaners if there are many inclusions. Protect from prolonged direct sunlight to prevent color fading.
Rarity & Value
Very common; value is determined by color depth ('Siberian' deep purple is most prized) and clarity. Large, clean specimens are affordable.
Special Characteristics
Color zoning (uneven distribution of purple), chevron patterning (if banded with white quartz), and potential for phantom inclusions.
Lore & History
Ancient Greeks believed it prevented intoxication (amethystos means 'not drunk'). Historically associated with royalty and the clergy; traditionally used for calm, clarity, and the third eye chakra.