By
Ashley Bailey, Monday, August 07, 2006 12:00 AM
Corundum Sapphire
Corundum is a gemstone that comes in just about every color. When corundum is red, it’s called ruby; when it’s blue, it’s called sapphire, and when it’s yellow, orange, pink, purple and, on occasion, green, it’s called fancy-color sapphire. ‘Fancy-color’ is just a way of saying a sapphire is some other color than blue.
Calling pink or yellow corundum sapphire would no doubt strike the ancient Romans as weird since "sapphirus" is the Latin word for blue. But that’s what slowly happened over the centuries. Sapphire became the gem family name for every shade of corundum but red. You don’t want to mess with the name that has the fame of ruby. That’s why lots of deep pink and purplish-pink sapphire is commonly offered as ruby in the Far East. Since there is no set cut-off point between ruby and pink sapphire, it’s often a judgment call.
Fancy-color sapphires were long the neglected members of the corundum family - all except padparadscha, an orange-pink blend whose color resembles both a tropical sunset and a lox belly. One of the rarest of all gems, padparadscha commands the kind of money reserved for the finest rubies - deservedly so. But a word of warning is necessary here:
The best padparadscha comes from Sri Lanka. Some decent material is also found in Madagascar. However, some retailers insist on calling brownish-orange-pink stones from East Africa ‘padparadscha’ or ‘African padparadscha.’ It is not padparadscha by any stretch of the imagination. That’s why we recommend buying padparadscha identified as such the American Gemstone Association’ Gem Trade Lab in New York.
While on this subject, be warned that many yellow-orange and light pink sapphires from Madagascar are converted into faux padparadschas by heating them with beryllium (a trace element that never occurs in corundum) to create a thick outer rind of padparadscha-like color. The process is called "bulk diffusion." If you see that term used to describe the color of any corundum, be aware that this form of color enhancement is universally condemned in the gem trade.
At present, pink and yellow sapphires are very popular. If they were more plentiful, no doubt purple sapphire would be just as hot. For the most part, Madagascar and Sri Lanka are the biggest producers of fancy-color sapphire. But Montana is no slouch either. Just remember that when buying fancy color sapphire, an identification report from a renowned gem lab is important. You want to know whether the stone you are considering owes its looks to nature, simple additive-free heating in an oven or a treatment involving use of chemical additives to produce color or hide imperfections. The days when sapphire come from mine to market with cutting the only processing are long gone. While we don’t mind simple heating, we draw the line at enhancement that depends of chemical additives.
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