It may come as a surprise to you if I tell you that the majority of gemstones in the market have been enhanced by a secondary process. Well, brace yourself for the truth. The fact is, color enhancing techniques are always used to alter the colors from the gemstone in the same manner a gemstone is cut to enhance its appeal.
With advancing technology, the different methods of color treatment are always evolving and getting more complex. Here’s a quick overview of a few methods used in the current market today…
Bleaching – high concentrations of caustic acid is used to bleach gems. Typically, pearls are bleached to give color uniformity.
Chemical Treatments and Reactions – typically considered both a chemical and heat process where acid baths and extreme heat are used together. This is done to give color uniformity and to saturate colors of gemstones. Important care is undertaken during this process as gems can quickly be ruined if the recipe and treatment conditions are not monitored correctly.
Coatings – An enamel lacquer or a liquid coloring agent is applied to fully change a gem’s color or to bring uniformity of color to the gemstone. Gems treated in this manner will have their colors altered through reflection and not via the absorption of light.
Dyes – More than 95% of gems such as jade, coral, opal, lapis lazuli and pearls are dyed in the industry. A good dye job is perfectly fine and will last you many years. A poor dye job may quickly lose its color and value.
Foiling – This is done by setting a foil within a closed bracket setting in a way that it cannot be detected. Foiling is usually done with a solitaire gem of lower quality to make it appear like it has gem quality.
Glass Filling – the rough is heated to several hundred degrees and an artificial filler is melted into the cracks and gaps. Borax, aluminium and silica are common filler material used to do this. This process is a bit controversial and is mainly performed on corundums from Asian countries.
A similar process called fracture filling is used to improve the clarity of diamonds and is available commercially to consumers.