Anahi Mine, La Gaiba Amethyst District, Sandoval Province, Santa Cruz Department, Bolivia Ex. Swoboda Collection Ametrine, sometimes also known in the trade as Bolivianite, is a naturally occurring variety of quartz. A mixture of amethyst and citrine, with zones of purple and yellow or orange, almost all commercially available ametrine is mined in Bolivia. The color of the zones visible within ametrine are due to differing oxidation states of iron within the crystal a result of there being a temperature gradient across the crystal during its formation. The present stone is a large circular-cut ametrine exhibiting excellent color zoning of bright citrine and rich violet, RHC8308. Weighing approximately 154.5 carats and measuring 35.89 x 24.16 mm