- Ametrine
Ametrine, also known as trystine or by its trade name as bolivianite, is a naturally occurring variety of
quartz . It is a mixture ofamethyst andcitrine with zones of purple and yellow or orange. Almost all commercially available ametrine is mined inBolivia , although there are deposits being exploited inBrazil andIndia .The colour of the zones visible within ametrine are due to differing
oxidation states ofiron within thecrystal . The different oxidation states occur due to there being atemperature gradient across the crystal during its formation.Artificial ametrine can be created by differential heat treatment of
amethyst .Legend has it that ametrine was first introduced to
Europe by a conquistador's gifts to the Spanish Queen, after he received theAnahi mine inBolivia as adowry .Most ametrine in the low price segment can surely be assumed to stem from synthetic material. Since 1994 a Russian laboratory has perfected the industrial production of bicolored
quartz crystals that are later irradiated to bring out the typical ametrine colors. Green-yellow or golden-blue ametrine does not exist naturally.External links
*http://www.gemstone.org/gem-by-gem/english/ametrine.html
*http://mineralminers.com/html/amtminfo.htm
*http://www.mindat.org/show.php?id=7606
*http://www.gia.edu/newsroom/issue/2798/2462/insider_newsletter_details.cfm#4
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