Ametrine
Quartz variety Ametrine · Semi-Precious Gemstone
Crystal System
Trigonal - commonly occurs as hexagonal-shaped prismatic crystals or in massive form
Mineral Group
Silicates (Tectosilicate subgroup)
Chemical Formula
SiO2 (Silicon Dioxide with Iron [Fe3+] impurities)
Formation Process
Hydrothermal - forms from silica-rich fluids at specific temperature gradients where iron impurities adopt different oxidation states
About This Crystal
A bicolor variety of quartz featuring distinct zones of purple (Amethyst) and yellow to orange (Citrine). This specimen is a small, polished, translucent to transparent fragment showing a clear transition between a pale lavender and a smoky-yellowish brown sector.
Physical Characteristics
Color: Bicolor (purple and yellow/orange); Streak: White; Luster: Vitreous; Fracture: Conchoidal; Specific Gravity: 2.65; Fluorescence: Generally inert
Optical Properties
Refractive Index: 1.544-1.553; Birefringence: 0.009; Optical Character: Uniaxial positive; No pleochroism in most specimens
Hardness & Durability
Origin Region
Primarily the Anahi Mine in Bolivia; also found in Brazil and parts of India and Canada
Hardness & Durability
Mohs Hardness: 7; Toughness: Good; Highly durable for all types of jewelry, though sensitive to extreme heat
Care & Maintenance
Clean with warm soapy water and a soft brush. Avoid ultrasonic cleaners and prolonged exposure to direct sunlight or high heat, which can fade the colors.
Rarity & Value
Uncommon; Single-source origin (Bolivia) makes natural bi-color specimens valuable, though synthetic and heat-treated versions are common and less expensive.
Special Characteristics
Features a unique bicolor zoning caused by differential temperature-dependent iron oxidation during crystal growth.
Lore & History
Legend states a Spanish conquistador introduced it to Europe in the 16th century after receiving a mine as a dowry from an Ayoreo princess. Traditionally associated with balancing masculine and feminine energies and stimulating both the crown and solar plexus chakras.