Gem Treatment Methods

At EmeraldandGemstones we consider and buy gemstones that have been treated only by accepted and approved gemstone enhancement methods.  If a gemstone in our stock  is enhanced it has been done so according to accepted world wide gemological standards.

Code:  E    = Routinely Enhanced Gem
RE = Rarely Enhanced/No Known Enhancement 
NE = No Enhancement



Fracture Filling:  In gemstones where tiny surface reaching fractures and fissures are common, they can be filled to diminish their appearance and help strengthen the stone.  Emeralds are an example of such a stone.  Emeralds are most often treated with natural oils. If necessary, the stone can be re-oiled by the owner to keep up its appearance. This method of treatment, if done properly, does not diminish the value of the stone. Epoxy resins can also be used to fill fractures, however oiling Emeralds and other like gems is the preferred practice.

Heat:   One of the most common treatment practices is to heat gemstones to alter or enhance their color.  This is a permanent process.  Certain gemstones are routinely heat treated such as: Aquamarine, Topaz, Sapphire, Tanzanite, Green Tourmaline and Zircon.  This treatment does not in any way diminish the value of the gem.

Irradiation:  Radiation can be used to alter or enhance the color of a gemstone.  Since this process is permanent and the results are stable, it is a widely accepted practice.  Gems which can be irradiated include: colored Diamonds, Quartz, Tanzanite, Tourmaline, Kunzite, Yellow Beryl, and a few others.

Diffusion:  Diffusion treatment is most often done to colorless or very light Sapphires to turn them blue.  Chemicals are applied to the surface of the gem, which is then heated for a prolonged period of time.  The result is a permanent color, but only on the surface of the gemstone.  The center remains colorless, and the color can be scratched off.  This practice is relatively new and not widely accepted within the trade.

Dye:   Gems which have small surface cracks are sometimes filled with dye in the form of colored oil and epoxy.  Dye can be used on certain stones such as Emerald and Ruby to enhance color.  Some stones, such as Lapis and Chalcedony are naturally porous and absorb dye well.  In fact “Black Onyx” rarely occurs naturally, most times it is dyed Chalcedony.

Coating:  Some gemstones can be coated with wax or lacquer to enhance their smooth, flawless appearance.  Another method of coating a stone is with a foil backing.  Although it is relatively uncommon, gemstone settings can be lined with foil (sometimes colored) to add sparkle and alter or enhance color.  These practices are considered deceptive and the customer should be wary of them.

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