September already?!
With the summer quickly wrapping up, and Fall just around the corner, I thought now would be a good time to put the spotlight on Sapphires, considering it is the birthstone of September.
Rare, exceptionally durable, and available in a very wide range of colors, sapphires are probably one of the most versatile gemstones available. Ranging in price from just a few hundred dollars to earth shattering and historical auction-house prices, sapphires can be available to most who seek out these beauties, no matter the budget. Although one of the more expensive gemstones available, that doesn’t mean you have to pay a small fortune for one that suits your fancy. From vivid royal and corn flower blues to vibrant purples and pinks and even spectacular greens, yellows and oranges, sapphires have a wide range of color that is sure to please, no matter what your taste might be. But where does one start?
What is a Sapphire?
Sapphires are part of the mineral family, corundum, which has a few inherent traits that make it perfect for everyday wear and versatility. Unlike some gemstones that are often softer and less durable, therefore not always ideal to wear everyday due to its susceptibility to abrasions and scratching, corundum ranks a 9 out of 10 on the Mohs scale of hardness (diamond being a 10), making it perfect to wear as an everyday fashion piece, or in recent years, a perfectly suited substitute for the more common diamond engagement ring. Corundum is an Aluminum Oxide (Al2O3), usually with trace amounts of other elements such as chromium, iron, or titanium to help form its many color varieties. The exceptional hardness of corundum also makes it ideal for gemstone cutting, allowing the lapidary to expose its high sheen, vitreous luster and sharp, contrasting facet junctions that make fashioning these rare beauties into many shapes with almost infinite faceting arrangement options. The big 4, as many in the jewelry industry refer to, consists of Diamond, Ruby, Sapphire, and Emerald. 2 of these (ruby & sapphire) are part of the corundum family. Both virtually identical in chemical and structural make-up, differs only by those tiny amounts of trace elements. Ruby being primarily colored by Chromium, and blue, yellow, and green sapphires being colored primarily by iron.
Okay! So now that you have a basic idea of what Sapphires are, let’s dive into the fun stuff.
What to look for?
Good news! Buying a sapphire can be substantially less complicated than buying a diamond. Unlike diamond buying, which can drive a person downright crazy, falling into a never-ending rabbit hole of cutting terms and technical jargon like crown angle, table percentage, symmetry, polish and clarity and color grades, the focus when buying a sapphire, like with most colored gemstones, will be primarily on the transparency and depth of color.
Once you’ve decided on which general color hue suits your desire, whether that is blue, green, orange, pink, purple, or the coveted Padparadscha sapphire (a peachy, orangish-pink color) then you can start focusing on the depth and undertones of the color that meet your style and budget. The deeper, more vibrant tones will typically command the highest prices, but if you’re on a budget, that doesn’t necessarily mean you can’t find the specific color you’re looking for; however, like anything in life, there will be a trade-off somewhere. In this case, it is usually in the transparency.
Transparency is a gemstone’s quality trait that allows light to transmit through the stone. A purer crystal, with less inclusions, usually allows more light to pass through, whereas more inclusions inhibit light, creating less transparency. Unlike a diamond, however, colored stones don’t typically receive a “clarity” designation, per se. This trait is usually articulated in the form of transparency. A sapphire with more inclusions will sometimes be stated as semi-transparent or translucent, and in many cases, when little to no light transmittance is observed in more commercial quality sapphires, it will be stated as semi-translucent or opaque.
What are the different types of treatments?
Great, you’ve narrowed down the color and transparency that meets your budget, let’s talk treatments. This one is huge and a focus of this article! To a lot of people’s surprise, treatments aren’t necessarily a negative thing. In fact, quite the opposite. Treatments allow a LOT more material to be used in jewelry that wouldn’t otherwise be that marketable. Whether improving a sapphires transparency or its color, treatments are an effective way to improve what would otherwise be more commercial material, to appear more desirable.
Heat:
I’ll let you in on a little secret, your sapphire is most likely heated. Huh? Yep! Most sapphires are cooked, baked, toasted, however you want to put it, the vast majority of sapphires on the market have been thermally enhanced in some way. But no worries, mother nature does it too, so it’s cool…or warm…errr…anyway, nature is basically a spinning ball of mostly solid mass with a molten liquid core, with a lot of crazy stuff in-between these layers. When conditions are just perfect for millions of years at a time, all this crazy stuff gets mixed together, heats and cools VERY slowly, and crystalizes over time to form gemstones. So, when mother nature doesn’t quite get it right, we humans have figured out a long time ago that we can simply stick sapphires in a glorified oven, turn the heat up a bit and finish the job, and in turn, create much more vibrant colors. Okay, so it might not be that simple. There’s some other stuff we must do so it actually works, like reducing or increasing oxygen levels, and sometimes using stabilizers so the crystals don’t crack or explode, but the idea is the same. Pretty neat though, right?
Unlike virtually every other treatment that can be applied to sapphires, heat doesn’t necessarily have to be disclosed. The FTC basically states that because it is a routine and common treatment of nearly all sapphires, it should be assumed that all sapphires have undergone some form of thermal enhancement. With that said, if a sapphire is accompanied by a credible lab report, independent of the company you purchased it from, and it states that no enhancement is present, consider yourself fortunate. These natural, untouched beauties, however, come with a price tag to match. Unheated sapphires can fetch 300% or higher prices because they’re simply so rare.
DISCLAIMER – PLEASE don’t go putting your sapphires in your oven at home or taking a torch to it. Bad things WILL happen. (Trust me, I’ve tried it. Bad things!)
Diffusion:
Diffusion treatments are unique in that it is a hybrid of thermal enhancement with added elements mixed in during the heating process using titanium, beryllium, or chromium. As the sapphire is being cooked, these added elements penetrate just below the surface, adding or changing the color of the sapphire. Since foreign elements are introduced in the heating process, this would go beyond the scope of standard thermal enhancement, therefore, would be a required legal disclosure.
Fracture filling:
This one is a little more invasive. Fracture filling involves using molten glass mixed with other heavy elements like cobalt or lead, which increase their refractive properties to match that of corundum. The filling gets sucked into all the surface reaching fissures and cracks and fills these voids in to mask a lot of the inclusions that would otherwise be downright ugly without this treatment. You might remember a few years back when some of the big department stores were selling rubies that were lead glass filled without disclosing this fact. Big no-no! As with all other treatments other than thermal enhancement , whether by inadvertent mistake and the seller didn’t know, or just manipulative and deceptive practice, it is up to the seller to disclose these treatments 100% of the time. It also significantly reduces the price. The sapphire that was fracture filled may be identical to one that isn’t; however, there will be a massive price reduction compared to the one that was filled. There are also some additional care requirements with fracture filled gemstones. For instance, direct heat should never be used, such as a torch when the jeweler goes to set the stone in a mounting. If you buy one that is loose and you have your local jeweler set it in a piece, be sure to let them know ahead of time. If they apply direct heat to it, the filler will melt and seep out, rendering the original murky and not so attractive crystal as it was unearthed from the mine. Also, aggressive solvents like acetone will literally dissolve the solution, yielding the same result as direct heat. No good
Dying:
Colored dyes are applied much the same way as fracture filling, but not quite as sophisticated as diffusion treatments. Unlike fracture filling, the purpose isn’t necessarily to improve the transparency, but much like diffusion, to enhance or add color. This occurs in the commercial market just like fracture filling. Lesser quality rough that may be less vibrant in color, is first cut and fashioned, then a colored dye or oil is used to improve the visual appeal. Again, aggressive solvents are to be avoided unless you want a faded and unattractive looking gemstone.
If treatments are disclosed, and the price paid is in line with the rest of the market of the ones with a similar/like treatments, treatments are NOT necessarily a bad thing. On the contrary, it simply provides the opportunity to obtain exceptionally beautiful sapphires at a more affordable price.
Further Reading
So now that we’ve covered the main points on the things to look for, you should have a decent handle on where to start. Determine the color and transparency that matches your style and budget. Ask your jeweler about any treatments applied to the gems you’ve narrowed down, and my advice is, if you’re spending over $2000 or so, I would recommend getting a lab report from a reputable company for the stone you’re looking to buy. And finally, enjoy the process. The same general rules apply to shopping for a sapphire or any gemstones for that matter, as I’ve mentioned in previous articles Tips For Buying Jewelry Online & Tips For Buying Jewelry In-Person. You can also read a little more information from a previous article published a few years ago.
I hope you found this helpful, and as always, any questions or suggestions for future articles, please let me know.
Joshua D. Lents FGA, GG
josh.l@gemlab.com
