Andesine (treated)

Item Description

Andesine is a rare variety of Plagioclase Feldspar which is extremely rare in gem grade pieces with orange or red colors. This new material was initially said to be discovered in 2002 in the Democratic Republic of Congo and as of the initial discovery of these stones, no more Andesine has been offered for sale. I have been told that this material is coming from Tibet, and some reports state that the rough is coming out of Inner Mongolia, China. The most well known red Feldspar is the "Oregon Sunstone" which is Labradorite, and has Copper content that caused a variety of colors ranging from red to pink to orange to green and rarely blue. There was much confusion surrounding the origin of these Andesine stones, and what exactly was causing the incredibly rich colors. This new red Andesine (also found in orange, green, blue and colorless hues) contains Copper, but it has been announced through extensive testing that SOME of these gems have been treated/diffused to create and intensify the colors, but according to the recent article written by George Rossman in Gems and Gemology, (Link here: http://www.palagems.com/gem_news_2011_v2.php#rossman ) a research team has found that there is indeed naturally occuring red and orange Andesine rough coming from the area. "The new material has been the subject of widespread concerns about its geographic origin and natural color. In fact, extensive studies of its composition, spectroscopy, physical appearance, and isotopic properties suggest that much of the red andesine on the market is the product of laboratory diffusion of copper into pale yellow andesine from Inner Mongolia". For a long time we were all lead to believe that these gems were not treated, and in some instances they certainly are, but this stone most likely has been heated to intensify the color. I have seen these gems being offered for sale for up to $400 per carat in some cases. This particular gem is a beautiful stone with a strong red color that looks beautiful in sunlight. This gem has very slight inclusions, which really cannot be seen when the stone faces up. It has a standard "Oval" cut.