| Original Message: Just a couple brief comments about blue and yellow sapphire |
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Russ - Heat treatment of sapphire started back in the 1970s when the Thais imported milky white "geuda" sapphire from Sri Lanka. "Geuda was frequently stored in large drums or used to gravel home gardens prior to the 1970s discovery that heat treatment can drastically alter the stone's color." --Wikipedia The Sri Lankans were mighty peeved when they discovered that the Thais had been buying geuda for pennies, heat treating it to blue, and then selling it for thousands. So, not yellow to blue, but milky junk to blue. Good deep yellow sapphire used to be rather scarce, and then it was discovered that diffusing beryllium into the crytal matrix at high heat would impart beautiful yellow and padparascha (pink/orange) and orange tones. Boy, did the poop hit the fan when gem dealers discovered that the rare padparascha sapphires they'd purchased were treated and not naturally colored stones. All rights reserved by Bead Collector Network and its users |
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