Monday, September 6, 2010

From Kashmir to Tanzania: How to Pick a Sapphire

September is sapphire month, and although I personally think that birthstone jewelry is just a sales trick, I will start my September blog entries by sharing what I know about this blue gem.

Sapphires come from all over the world, but some countries of origin are much more highly prized than others. The most valuable is a Kashmir. I’ve never seen one myself, nor has anyone I know. That’s how rare they are. The mining of Kashmir sapphires is pretty much finished as far as I know, so all that’s left are collector’s items that are not in circulation.

In more or less the order of value, here are the other main sources for sapphire: Burma (Myanmar), Ceylon (Sri Lanka), Thailand, Australia, Tanzania. Burmese sapphires have a rich, medium dark royal blue color; they look a little like kyanite. Burmas are by far the most expensive sapphires on the market today, and are hard to get. Below is a picture of my unheated Burma sapphires here. If you want a pair like that, figure on $250 just for the stones. That gives you an idea. The Burmas I can get come from old stock – they are old mine, in dealer’s lingo. They were cut a long time ago.

Burma Sapphires

Ceylon sapphires are mostly lighter, and they often have zoning when you turn them over. Zoning means uneven distribution of color with lighter and darker tones (zoning seen from the back is acceptable, so long as it isn’t obvious from the front – Ceylon sapphires often have darker and lighter spots so they have to be cut with the dark part in the culet for it to make the whole stone look blue). Some Ceylon sapphires are purplish blue, and these often go at a premium. Since they are lighter, Ceylon sapphires are generally cut with a lot of depth, which adds to the weight, and thus the price. Here's a picture of a small suite of Ceylons so you can get an idea.

Ceylon Sapphire Suite

Thai sapphires are very dark blue, and have to be cut shallow so they don’t look too black. Australian sapphires, meanwhile, have a greenish tint. Turn the stone over to see the tint, or put it next to a Ceylon, then you see it right away (see the picture below, small Ceylons are on the left, Australian in the middle and the right). Australian sapphires can also be very dark and are often cut shallow. Another advantage of a shallow stone is that it is easier to set and find settings for. Deeply cut stones are hard to work with.

Ceylon and Australian Sapphire Pairs

Tanzanian sapphires are mostly a grayish blue. Tanzania is more known for fancy (or multi) color sapphires, but as of late, lots of blues have been coming out of Tanzania as well.  I have a pair of trilliant cut earrings listed, you can have a look on my etsy.

Sapphire prices also depend on clarity and size, of course. Sapphires should never be as included as rubies or emeralds, but if you want an unheated stone, which will go at a premium, you may see more inclusions and less brilliance.

A couple of weeks back, I had the pleasure of sifting through a parcel of unheated and a parcel of heated Ceylons that were between 1 and 3 carats. Normally I would not have been privy to this because it involved a transaction between two dealers, and gemstone dealers are very secretive about whom they buy their stones from. When a dealer approaches the booth of another dealer, he tries to do this when there are no customers, or he’ll be asked to return at the end of the day. Well, it was the end of the day and I was still there, so the dealers agreed I could stay and look, as well as be offered the same prices. That said, I still couldn’t really afford anything in these parcels. But I learned something very valuable: side by side, most of the heated stones looked very glitzy and clean, many of the unheated stones seemed a little duller. I saw a few amazing pieces though, among them a 1 carat deep cut yellow Ceylon and a 3 carat blue one that was just stunning. I probably should have bought it for myself. (But I always feel like buying things for myself).

What, then, is the big deal about a sapphire’s being heated? Well, mostly it’s not a big deal, it is mainly about personal preference. I have access to unheated stones, and I love knowing that their beauty is as nature intended. You should know, however, that 90% or more of sapphires on the market are heated. If you own sapphire, it is probably heated. Stones are heated to improve color intensity and clarity. According to Newman’s Gemstone Buying Guide (a valuable resource), you should assume that any sapphire you buy is heated. And if you ask a gemstone dealer if his sapphire is heated, he will probably act offended, saying “yes of course, they are all heated,” so as not to diminish the value of his merchandise.

I cannot personally tell if a stone has been heated, but the rule is that if you ask a dealer about heat treatment he must answer you honestly. Also, if the stone is unheated, the dealer will probably tell you this because it is an extra selling point, as well as a justification for a higher price. Lastly, any gemstone dealer who specializes in sapphire should be able to detect evidence of heat treatment under magnification.

On occasion, sapphires are also fracture filled or diffused. Diffusion treatments are common for star sapphires, for instance, because it brings out the star. Unfortunately, it turns the star sapphire grayish. I don’t recommend diffusion treated stones, and fracture filling is also not an acceptable treatment. Heat treatment is the only acceptable treatment for faceted sapphire.

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