A Worthy Gemstone Appraisal
Last updated: July 10, 2018
When Do You Need a Gemstone Appraisal?
A gemstone appraisal tells you what a gemstone is worth. If you recently purchased a gemstone, you know its value. But if you own gemstones that you inherited, received as a gift, or purchased at an estate sale or auction, you may wonder “how much is my gemstone worth”? What a gemstone is worth changes over time: that is to say gemstone market value fluctuates up and down. This means that you need to update your gemstone appraisal every few years to make sure that your gemstone is insured at the correct replacement value: if it is too high, you are paying for insurance you don’t need but if it is too low, you won’t be covered in case of loss. While there are several ways to get a gemstone appraised it is most important that whoever is examining your gemstone is fully qualified and objective.
What Should a Gemstone Appraisal Include?
An appraisal should include much more than the value of your gemstone. A professional appraisal must included a detailed gemological description of the gem and its setting, which often requires removing a gem from its mounting. It should include a complete description of a gem’s carat weight, size, color, clarity, cut, whether a gem is natural, whether it has been enhanced. Some appraisals will also include information about where a gemstone was mined but this is always an opinion and cannot always be determined reliably.
Gemstone Appraisal Locations
Many jewelers do appraisals so your local jeweler may be a good place to get your gemstone appraised. This service is not free: it requires time and expertise. Look for a professional credential, including from the American Gem Society, National Association of Jewelry Appraisers, Certified Insurance Appraiser, ISA, or CAPP. Make sure you tell the appraiser the purpose of the appraisal. An appraisal for retail replacement value will be quite different than an appraisal for selling a gemstone, which will use the wholesale liquidation value. Exercise caution when a jeweler provides an appraisal with your purchase that indicates a gem is worth more than you paid or assesses a gem purchased from a competitor as worth less than you paid: these documents are commercial in nature and not objective.
Gemstone Certificates and Laboratory Reports
A gemstone laboratory is the best place to receive a detailed and objective gemstone report with information on quality, origin and treatments. They use high-tech equipment to identify and describe a gemstone in detail. The following institutes around the world are the most well-respected for gemstone laboratory reports:
GIA: Gemological Institute of America
AGS: American Gem Society
GGL: Gubelin Gem Lab
SSEF: Swiss Gemmological Institute
GRS: GemResearch Swisslab
Gemstone certificates include information on color, clarity, carat weight, dimensions, whether or not a gemstone has been enhanced, whether a gemstone is lab-grown or naturally mined, and the gemstone country of origin. A report will also mention any chips or scratches. What a lab report does not include is a gemstone’s value. For that you need a gemstone appraisal.
Gemstone Value Factors: The 4Cs of Gemstones
Gemstone Carat Weight
This most basic and familiar aspect of gemstone valuation is carat weight: one carat is equivalent to 0.2 grams. What might surprise you is that because different gem varieties have different densities, one-carat gems of different varieties are different sizes. A one carat emerald is much larger than a one-carat sapphire. Conversely, when you are matching sizes, you will need different carat weights. A 6mm round diamond weighs about 0.90 carats, a 6mm sapphire weighs about 1.05 carats, and a 6mm round emerald weighs about 0.80 carats. Different cutting styles can result in even more dramatic differences, since each gem handles light a bit differently: the ideal proportions are different for each gem.
The scale for gem color is entirely different from that of a diamond. The color scale goes from very light to dark. For most gem varieties, it is color saturation that is the most important gem value factor. The more vivid the red of ruby, the blue of sapphire or the green of emerald, the more valuable that gem will be, all other things being equal.
It is common that gems are treated to enhance their color. Treatments include; heating, drilling, fracture filling, and diffusion.
Unlike diamonds, most gems have inclusions. These let you know that a gem is natural. In general, the paler the color, the more inclusions affect value, since they are easier to see. Some gems, like emerald and pink tourmaline are very difficult to find without some inclusions so gems without eye-visible inclusions are very rare and valuable.
A well-cut colored gemstone exhibits even color, an acceptable number of inclusions, good brilliance and even color. While there are several shapes that hold different value due to popularity at any given time, it is not entirely related to the quality of the cut. Standard Gemstone cuts are; Round Brilliant Cut, Oval Cut, Baguette Cut, Square Cut, Trilliant Cut, Pear Cut, and Emerald Cut.
Gemstone Treatment and Value
Most gemstones on the market today have been enhanced by treatments to improve their color or clarity. Common enhancements include heating sapphire and ruby to improve color, oiling emeralds with resin to decrease the visibility of inclusions, and irradiating blue topaz to create its color. Fine rubies, sapphires and emeralds that have not been enhanced command a premium and will be accompanied by lab reports. Some treatments have a dramatic effect on value: lead glass filling and diffusion treatment of ruby and sapphire result in dramatic differences in appearance and gems treated in these ways are much less valuable.
Gemstone Country of Origin
Certain mines are known for producing very fine gemstones. Fine specimens of gemstones from these localities command a premium. Burma rubies from Mogok, Kashmir sapphires, Colombian emeralds, and Russian demantoid and alexandrite are attractive to collectors and can sell for more than similar looking gems from other places if they have a lab report that confirms their country of origin. But origin alone is never a guarantee of value. Famous mines also produce very low quality gems.
Natural vs Genuine Gemstones
Natural gemstones are those found in nature, with no interference from humans. By the time they appear in our jewelry they've been cut or polished, but they've not been altered or treated in other ways. A genuine gemstone is the real thing, but has been treated in some way to enhance its appearance. Enhancements allow jewelry manufacturers to improve the look of gemstones that consumers may not have purchased otherwise. Treated gemstones are not fake, but they are no longer considered natural. If naturally "perfect" stones were the only gems available, most of us wouldn’t be able to afford them.
Synthetic vs Simulated Gemstones
A synthetic gemstone is grown in a laboratory, not mined in the ground. So a synthetic ruby is actually ruby but it wasn’t found in nature, it was created by man. Simulated gems just look similar to the gem they represent. Cubic zirconia is the most well-known simulant: it looks like diamond but it isn’t diamond. A lab grown diamond, on the other hand, is actual diamond that is made by man.