By now I hope you're all looking at your stones and wondering what the heck do I actually have in my jewelry. As well you should, because gemstone treatment disclosure is a touchy issue for most jewelers. Either because they don't think they can sell a stone they reveal to be treated, or because they simply don't know if the stone they are selling is treated, or because they don't even know about gemstone treatments at all (unfortunately this is far more common in the industry then you can imagine), many jewelers simply don't talk about the issue. This isn't to say none of them do but I believe treatment disclosure probably still runs well below the 50% rate based on the number of people who come in my store already wearing treated stones who have no idea about treatments. So the next question is what treatments are acceptable.
In my shop I will sell stones that have been heated, irradiated, occasionally bleached (pearls), and with emeralds stones that have been oiled or fracture filled. I will not sell diffusion treated stones, dyed stones, rubies heavily heated (more on this later) or any other types of treatments. Why do I draw this line? Heated, irradiated, and bleached gem materials will not ever revert or change in color. All of the other treatments are not permanent, or if a stone was damaged and had to be recut would not have the same color, or take the treatment level to a point that makes the stone something it could truly never be. With emeralds there is so little untreated material available that it is simply impossible to purchase anything that hasn't been. Oils, and some fracture fillers, do leach out over time and can change the appearance of the stone so extra care is necessary with emeralds. This doesn't mean that stones that have been treated in other fashions shouldn't be sold anywhere. It just means that I won't sell something that is subject to change like that and that the stones should be priced accordingly.
So let's talk about individual gemstones and their treatments and we might as well start at the top of the pile with diamonds. Diamonds have been subjected to treatments far longer than many people realize. It started with attempts to change their color through irradiation. Unfortunately when they first started this they had no real idea what they were doing or dealing with and a number of diamonds were produced that became radioactive and stayed that way, leading to a number of finger disfigurements, back in the early days of our playing around with radioactivity. Watch dials were also a problem for people when they used radioactive materials to make them light up. Needless to say these issues put a quick end to that specific type of treatment. However it was discovered later on how to irradiate stones without any residual radioactivity and diamonds have been irradiated to change their colors for quite a few years.
The next treatment that came up with diamonds was laser drilling. In playing around with lasers and diamonds it was discovered that a pinpoint sized hole could be drilled into the stone to dark inclusions inside the stone and then that a bleaching agent could be introduced to whiten the dark inclusions. When I got my graduate gemologist degree in 1984 this had already been going on for quite a few years.
Since then we have added fracture fillings (a substance is forced into inclusions in the diamonds to make the inclusions less apparent), and high pressure/high temperature treatments to raise the color grade of certain diamonds. The interesting thing about this is that only certain types of diamonds (there are a number of different types of diamonds but this issue gets far too technical to discuss here) actually will take this treatment so there are a limited number of stones that could be subjected to it.
Please remember that all of the stones I am talking about here are natural gem materials that come out of the earth. In my last posting on the subject I will get into synthetics and simulants. In my next article I'll talk about sapphire and ruby treatments.
The rings pictured above are my latest stacking set with pink, purple and blue sapphires.