As collectors, we are always on the lookout for that special piece of jewelry or gemstone to enhance our collections. Buy from sources that are either known to you, or choose dealers or online stores that are known to be reputable. Once you've made a successful purchase, it's wise to continue to deal with those you trust implicitly, sellers with a proven track record. Although synthetic gemstones and the jewelry made with it are, in many cases, desirable, you want to avoid buying a synthetic stone when you're after an authentic one.
Value is not only in the eye of the beholder, but a truism when dealing with gemstones. Synthetic stones are marvelous pretenders that simulate their real counterpart’s characteristics very closely in many cases. It is so easy to be fooled.
Advice and Commentary from Barbara W. Smigel, PhD. Graduate Gemologist, GIA
We asked Barbara W. Smigel, PhD. Graduate Gemologist, GIA, how to tell the difference between real and synthetic stones.
#1 You Can't! Not even a gemologist can make a sight identification with accuracy; tests, equipment and training, that the average person doesn't have, are required to make an accurate identification. The best way to avoid getting burned is to stick with well- established firms or deal with individuals with credentials from well-known institutions, and who have a money-back guarantee for the authenticity of their goods.
#2 There are three tasks in gem identification:
a) What is it?
b) Is it natural or synthetic?
c) What type of enhancement, if any, has it had?
To illustrate, we see a red transparent stone, let's say a round brilliant, that is very sparkly and has no eye-visible inclusions:
#1 What is it? This is the easiest of all for a gemologist to answer, because red glass, natural red spinel, natural red garnet, natural ruby, synthetic ruby and many other gems can look like this, but they will all differ in optical, physical and chemical properties such as refractive index, optic character, density, fluorescence, pleochroism, hardness, etc. So we test it and rule out all the major possibilities except ruby. Great. But is it natural or synthetic, we don't know yet, as a synthetic ruby IS ruby and has all the same readings as a natural one. On to question two.
#2 Natural or synthetic? There are many types of synthetic rubies and some are relatively easy to spot with a trained eye and the right equipment, such as a gemological microscope with immersion liquids and/or diffused lighting. For example, if we see internal structures under magnification called "curved striae" -- end of story, the stone is a synthetic ruby. If we see a microscopic inclusion of a sort called a "fingerprint" -- we have a natural stone. However, what if the stone is flawless, or if the inclusions are ambiguous, that is they can be seen in both natural and synthetic stones (very commonly, this is the case). At that point, a big gem lab with expensive high tech equipment may be the only way to get an accurate identification.
#3 Is it enhanced? Let's say we determine that we have a ruby of natural origin. It still may have been enhanced by heat, diffusion, coating, filling or other methods to improve its clarity and color. Again, some of these treatments are easy to spot if you have the equipment and knowledge, some are not. For example, an inclusion called a stress fracture is indicative of heating, a fine and intact network of rutile fibers indicates no heat, but there is a great middle ground here too, where it can be very difficult to determine the enhancement status of a gem.
Quite literally, there is an arms race going on between gem synthesizers and treaters who are seeking to make more and more realistic-looking synthetics and simulants, either for honorable or dishonorable reasons, and the gemologists who are trying to find ways to detect each new treatment or synthetic.
Now, in specific regard to CZ -vs- diamond -- #1 What is it? still applies for the average consumer, but jewelers have a simple tool that costs about $100.00, that tests the thermal conductivity of the stone with a metal probe and reads either diamond or not diamond. Pawn shop owners use these too, as do those dealing in vintage and antique jewelry. The recent introduction of a new diamond simulant, Moissanite, has necessitated a new generation of diamond testers because Moissanite will pass the thermal test as a diamond. This new diamond tester uses electrical conductivity and easily separates diamond, which doesn't conduct, from Moissanite, which does.
Crystal Enchantments: A Complete Guide to Stones and Their Magical Properties
