Amethyst
Quartz var. Amethyst · Semi-Precious Gemstone / Mineral Specimen
Crystal System
Trigonal; typically occurs as six-sided prismatic crystals ending in six-sided pyramids. This specimen is a small tumbled or water-worn fragment, approximately 12mm in length.
Mineral Group
Silicates (Tectosilicate subgroup)
Chemical Formula
SiO2 (Silicon Dioxide) with trace amounts of iron (Fe3+) and irradiation centers
Formation Process
Hydrothermal formation where silica-rich fluids cool in cavities (geodes or veins). The purple color is caused by trace iron impurities within the quartz lattice being exposed to natural gamma radiation.
About This Crystal
Small, translucent fragment showing a rich violet to purple-lavender color. It exhibits a vitreous (glass-like) luster and slight color zoning with lighter and darker purple bands visible within the stone.
Physical Characteristics
Color: Violet to purple; Streak: White; Cleavage: None; Fracture: Conchoidal; Specific Gravity: 2.65; Tenacity: Brittle; Fluorescence: Typically inert under UV light.
Optical Properties
Refractive Index: 1.544-1.553; Birefringence: 0.009; Pleochroism: Weak to moderate purple/reddish-purple; Optical Character: Uniaxial positive.
Hardness & Durability
Origin Region
Major sources include Brazil (Rio Grande do Sul), Uruguay, Madagascar, and Zambia. Often found in volcanic geodes and hydrothermal veins.
Hardness & Durability
Mohs hardness of 7. It is durable for most jewelry types but can be scratched by harder stones like topaz or corundum. It has no cleavage, making it resistant to chipping.
Care & Maintenance
Clean with warm soapy water. Avoid ultrasonic cleaners if there are major inclusions. Store away from direct sunlight for long periods, as heat and UV light can cause the purple color to fade to yellow or colorless over time.
Rarity & Value
Very common mineral; value is determined by color depth (darker 'Siberian' purple is higher value), clarity, and size. This small specimen has modest collector value but is a classic example of the variety.
Special Characteristics
Displays distinct conchoidal fracture patterns typical of quartz and color zoning where growth layers trapped different concentrations of iron atoms.
Lore & History
Historically worn by Ancient Greeks to prevent intoxication (from the Greek 'amethystos', meaning 'not drunken'). It has been a stone of royalty and is traditionally associated with the Crown Chakra, peace, and meditation.