Treatments of Gemstones

S
Y
M
B
O
L		Definition
AIndicates either a gemstone that is not currently known to be enhanced or one that is so rarely enhanced that to give it an "E" symbol would mislead the public.
Example: Amethyst is rarely known to be treated.
EIndicates that this gemstone is routinely enhanced.
NIndicates this particular gemstone is natural and has received no enhancement and the seller will guarantee this.
BIndicates that Bleaching of the gemstone has been done. Bleaching is the use of chemicals or other agents to lighten or remove a gemstone's color.
Example: 'Blonde Tigereye" is enhanced in this manner
CIndicates that a Coating has been used as a surface treatment such as waxing, lacquering, enameling, inking, foiling, or sputtering of films to improve appearance, provide color or add special effects.
DIndicates that Dyeing has occurred. Dyeing is the introduction of coloring matter into a gemstone to give it new color, intensify present color or improve color uniformity.
Example: Agate is sometimes enhanced in this manner.
FIndicates the gemstone has had Filling or Infilling or Stabilizing of some form. This is the filling of surface-breaking cavities or porous gem material with colored or colorless glass, plastic or other hardened material to improve appearance, durability, and/or weight.
Example: Turquoise is commonly enhanced in this manner.
GIndicates the gemstone has undergone some form of Gamma or Electron Irradiation. This is the use of gamma and/or electron bombardment to alter a gemstone's color. May be followed by a heating process ("H").
Example: Blue Topaz is commonly enhanced in this manner.
HIndicates the stone has been heated to effect desired alteration of color, clarity, and/or phenomena.
Example: Sapphire is commonly enhanced in this manner.Example: Citrine is commonly enhanced in this manner.
LIndicates the gemstone has undergone the use of a laser and chemicals to reach and alter inclusion.
Example: Diamond is sometimes enhanced in this manner.
OIndicates the introduction of a colorless oil, wax, natural resin, or unhardened man-made materials into fissured or porous gemstones was made to improve appearance.
Example: Commercial grade Emerald is commonly enhanced in this manner.
RIndicates the gemstone has undergone Irradiation. This is the use of neutron or a combination of neutron with any other bombardment to alter a gemstone's color. May be followed by a heating process ("H").
Example: Blue Topaz is commonly enhanced in this manner.
UIndicates the gemstone has undergone Diffusion which is the use of chemicals in conjunction with high temperatures to produce a relatively shallow subsurface layer of color and/or asterism-producing inclusions.
Example: Diffusion treated Sapphire is enhanced in this manner.