Joseph DuMouchelle Offers Professional Insight Into Gemstone Treatments and Value Factors

Avatar for Ebiz Editor
Joseph DuMouchelle Gemstone Treatments and Value Factors Joseph DuMouchelle Gemstone Treatments and Value Factors

Gemologist Joseph DuMouchelle explains gemstone treatments and enhancements, and how such processes affect values.

When it comes to gemstone pricing, applied treatments and enhancements, versus a stone remaining natural beyond cutting and polishing, represent among the most critical factors in determining values. A graduate gemologist, appraiser, and auctioneer, jewelry expert Joseph DuMouchelle explains more on the subject.

Defined by experts as any treatment process beyond cutting and polishing a stone for color, clarity, or durability, so-called ’enhancements’ are common in the gemstone market according to DuMouchelle, a graduate gemologist, appraiser, auctioneer, and co-founder and president of Joseph DuMouchelle Fine & Estate Jewellers, LLC. Alongside fellow co-founder and partner Melinda ’Lindy’ Adducci, the international auction house business enjoys locations in New York, Michigan, and Florida, and regularly sells to clients in more than 80 countries worldwide.

“Treatments and enhancements may be carried out in order to improve the appearance or wearability and durability of a stone,” he explains, “although it’s important to consider the potential effects on value before taking this route with any gemstone.”

Natural gems can, says DuMouchelle, routinely command as much as an 80 percent or more premium over so-called ’enhanced’ specimens, which have undergone, for example, radiation exposure or heat treatments. “Natural sapphires command significantly higher prices today than their arguably often somewhat more attractive and colorful, to many an eye, treated or ’enhanced’ counterparts,” he explains.

In other cases, however, and with gemstones such as citrine, a variety of quartz, little or no demand exists for natural stones. “Accordingly, while treating citrine has no negative effect on the value of the stone, with no demand for natural examples, opting not to ’enhance’ it means it has no tangible value in the first place,” DuMouchelle explains.

Further to radiation exposure and heat treatments, other forms of enhancement involve coating, dyeing, fracture filling, oiling, and diffusion treatments. With the exception of oiling, all of these processes are permanent, according to DuMouchelle. “Ultimately, value factors tied to treatments and enhancements are markedly more significant with larger, rarer gemstones,” suggests the expert.

“Accordingly, it’s important that when dealing with valuable, or potentially valuable, specimens, including rough or uncut examples, anyone unsure on the price implications of applying treatments and other enhancements should consult with a qualified expert in the first instance,” the Joseph DuMouchelle Fine & Estate Jewellers co-founder adds, wrapping up.

Joseph DuMouchelle is a member of the international board for the Gemological Institute of America Alumni Association and former head of the Accredited Gemologists Association. To learn more, please visit