Gemstone Treatment and Enhancement

Gems are treated in different ways to improve their appearance. Some of these procedures are centuries old, while others are relatively new. Within the industry, some of these practices are taken as commonplace, while the gem buying public’s awareness of these treatments has been much lower.
… In this day of full disclosure and public awareness, the subject is coming to the forefront. Many industry officials are concerned that too much information will confuse customers and hurt sales. Others feel the public’s right to know outweighs these concerns.
… One certainly can confuse the public, as gem enhancement covers such difficult subjects as the physics of light response to molecular structure. However, some general comments are in order.

… First, let me clarify that the term “natural gems” refers to those formed in the earth, whether or not they have been treated after mining. This, in contrast to “lab created,” “man made” or “synthetic” gems.
… The most common form of enhancement is heat treating. This is so common with corundum, (ruby and sapphire,) it is recommended that jewelers inform their customers that they are “probably heat treated.”
… ”Probably?” That doesn’t sound very professional. What is happening here is that the procedure so closely resembles what happens in nature, that one can’t always tell if they have been treated after mining. Microscopic examination will sometimes reveal evidence of heating, but lacking that there is no way to tell if the heat treatment was done before or after mining.
… A similar situation occurs with aquamarine. If properly heated, it will lose it’s green tint and become a pure blue. This is also identical to what happens in nature and there is no way of telling if it was done after mining. However, since most of the material coming out of the ground does have a green tint, it is recommended that the pure blue gems are described as “probably heat treated.”
… Very closely related to this is the treatment of blue topaz. Actually, it is a treatment of colorless topaz to turn them blue. This is done in two steps. First the rough is subjected to radiation to modify the sharing of electrons between certain atoms in the crystal structure. This turns the topaz brown. Then they are heated to become a stable blue color.
… ”Radiation!” Yes, this is one of the reason industry officials are reluctant to use full disclosure. Radiation is a scary word and telling someone a gem has exposed to it will certainly drive customers away.
… However, this too exactly duplicates what happens in nature. Many gem crystals get exposed to radioactive elements during their formation. That doesn’t mean they become radioactive, nor does it imply anything else. In fact, many gems seem to have beneficial effects on their wearers.

… The above represent some of the most common examples of gem enhancement. The industry has never felt a need to disclose treatments that are indistinguishable from the processes that occur in natural formation. However, there is one other common enhancement that falls into an entirely different category. That is the oiling of stones.
… Some gems, most notably emeralds, have internal fractures. Light reflects off of their surfaces, which seriously effects the clarity and brilliance of the gem. However, by simply filling them with a substance of similar optical properties, the tiny cavities once again become transparent. The difference in the appearance of the finished gem can often be startling!
… Now, how chicken this is depends on your point of view. To the gem cutter, this is a serious problem. Those tiny fractures represent areas of weakness that have to be considered in the cutting process. If masked with oil, the risk of damage during cutting becomes much greater.
… To the proud owner of an emerald, the improvement to it’s appearance is well worth it. One doesn’t see the oil, it simply allows the natural beauty of the gemstone to stand out. Both the emotional and the monetary value of the gem are considerably enhanced.
… However, the owner should certainly be made aware that it needs special care. Continual washing of dishes while wearing an emerald ring can cause it to lose its brilliance. Vigorous cleaning methods, like using heat or immersing in an ultrasonic jewelry cleaner can be disastrous.

… There are many other ways gems can be enhanced. Inexpensive ones are often dyed, the porosity of turquoise is often sealed so body oils don’t discolor them, etc. However, the above represent the most common examples one is likely to come across.

by Don Clark CSM