Ametrine
Quartz variety Ametrine · Semi-Precious Gemstone / Mineral Specimen
Crystal System
Trigonal; typically occurs in hexagonal prisms with rhombohedral terminations
Mineral Group
Silicates (Tectosilicate group)
Chemical Formula
SiO2 with Fe3+ and irradiation centers
Formation Process
Hydrothermal; forms in carbonate rocks through the precipitation of silica-rich fluids where a precise temperature gradient allows different oxidation states of iron (amethyst/citrine) in the lattice
About This Crystal
A bi-color variety of quartz featuring distinct zones of purple (amethyst) and yellow to orange-yellow (citrine). This specimen appears as an elongated, rough prismatic crystal fragment with vitreous luster and translucent transparency, showing a clear divide between the violet and pale yellowish-green sectors.
Physical Characteristics
Color: bi-color purple and yellow; Streak: White; Cleavage: None (indistinct); Fracture: Conchoidal; Specific Gravity: 2.65; Fluorescence: Generally inert under UV light.
Optical Properties
Refractive Index: 1.544-1.553; Birefringence: 0.009; Pleochroism: Weak to moderate; Optical Character: Uniaxial positive; features double refraction.
Hardness & Durability
Origin Region
Anahí Mine, Santa Cruz Department, Bolivia (the only significant commercial source)
Hardness & Durability
Mohs Hardness: 7; Toughness: Good; Stability: Stable to light but sensitive to extreme heat which can cause color fading or shifts.
Care & Maintenance
Clean with warm soapy water. Avoid ultrasonic or steam cleaners. Store away from prolonged direct sunlight to prevent fading of the purple zones. Store separately from diamonds or sapphires to prevent scratching.
Rarity & Value
Rarity: Rare (due to limited geographic origin); Value: Moderately priced, dictated by the sharpness of the color split and saturation; common treatments include irradiation or heating of lower-grade quartz to simulate the appearance.
Special Characteristics
Color-zoning: The unique coexistence of two color centers (Amethyst and Citrine) within a single crystal lattice due to temperature gradients during growth.
Lore & History
Legend suggests the crystal was first introduced to Europe in the 1600s by a Spanish conquistador who received the Anahí mine as a dowry. In metaphysical lore, it is believed to combine the serene properties of amethyst with the energizing properties of citrine, balancing the crown and solar plexus chakras.