Treatment and Enhancement Guide
Treatment and Enhancement Guide:
Most items that we come into contact with every day have been treated in some way; clothes have been dyed, houses have been painted, and most wood has been pressure treated. Gemstones are not any different. When a gemstone is forming deep within the earth, natural heating and pressure occur. In order to bring more gemstones to the public, many companies continue that process with additional heating, pressure, or other treatment techniques. without treatment techniques, only the very, very wealthy would be able to afford the wide range of colored gemstones created by nature. it is estimated that up to 80% of all gemstones have been treated in some way. The following guide will provide additional information as to what possible treatments stones have experienced.
the following codes and definitions are adapted from the american gem trade association's gemstone enhancement manual, edition 6.1 june, 1997, which is the industry standard for disclosure to consumers.
1) N: those natural stones which are not currently known to be enhanced by any methods, such as spinel, and therefore can safely be presumed untreated. The symbol "n" is used for these and may also be used in the case of other stones which are sometimes or often treated, which in the particular case are un-enhanced. to use this symbol on sapphire, for example, which is generally heated means that the seller certifies that the particular stone was not heated and can supply a document such as an invoice or lab report so stating.
2) E: Those natural stones which are routinely enhanced by traditional methods, the particular stone given this designation, may or may not be enhanced. For example, since most emeralds are oiled an e would indicate such treatment, but would not cover non-traditional methods such as hardened plastic resins (like opticon) which would require specific enhancement codes such as those listed below. Another example would be the use of e for aquamarine, which in most cases is heated prior to the sale of the rough to remove greenish tints. If the seller knows what specific treatment has been used, then a more specific code should be used.
3) Those gemstones for which definite information on standard treatments is known, or to which n and e codes do not apply, due to non-traditional treatments must disclose the specific treatment with the appropriate code. For example, a ruby which has had fractures or cavities filled with glass would receive an i (infilling) code as described below. A morganite, which is known to have been heated, would receive an rather than the less specific, e.
b: Bleaching - use of chemicals to lighten or remove a gem's color
c: Coating - use of surface treatments such as films, lacquers, etc. To provide color or other special effects. note: this type of treatment is not permanent and can chip or wear off. do not use harsh solvents or chemicals on jewelry with this type of treatment.
cr: Created/synthetic stone ? This designation is used for any stone that is synthetic or laboratory created.
d: Dyeing - the introduction of coloring matter into a gem to give it a new color or greater intensity
f: Filling - incorporation of colorless borax or other substances into cracks as a by-product of heating the stone, used only if such material is visible at 10x.
g: Gamma/electron radiation - the use of gamma or electron irradiation for the purpose of changing a gem's color, may be followed by a heating process to stabilize the color. such stones do not exhibit residual radioactivity.
h: Heating - the use of heat to clarify, change color or create phenomena in gems. any filler materials, which enter the gem, as a result must not be visible in fractures at 10x magnification.
i: Infilling - the intentional filling of surface breaking cracks and cavities with a foreign material such as synthetic resins with hardeners (opticon), glass or plastic.
l: Lasering - the use of a laser to drill into a stone and remove or alter an inclusion, refers specifically to diamonds
o: Oiling or resin infusion - the intentional filling of surface breaking cavities and cracks in transparent or translucent gems with a colorless oil, wax, resin or man-made unhardened resin.
r: Irradiation - the use of neutron bombardment to alter color. This process creates residual radioactivity and such stones must receive a nuclear regulatory commission safety release prior to sale. this usually used in combination with other radiation and or heating treatments.
s: Bonding - the intentional use of a colorless bonding agent (usually plastic) within a porous gemstone.
ta: type a jade - natural jade enhanced only with wax.
tb: type b jade - natural jade that is bleached in acid to remove undesirable staining, then impregnated with wax or polymers.
tc: type c jade - natural jade that is dyed and sometimes bleached and impregnated with wax or polymers.
ds: diffusion - the use of specific chemicals during a high temperature heating process for the purpose of penetrating the surface layer (usually to a slight depth only) with coloring or star-making chemicals. such treatment is not generally accepted and stones sold with this enhancement must be specifically labeled as diffused.
w: Waxing/oiling - the impregnation of colorless wax, oil or paraffin into porous opaque gems to improve appearance.
dbl - doublet- the use of a thin layer of natural stone adhered to a backing material. The doublet backing material is used to thicken and give strength to the item.
tpl - triplet- the addition of a clear protective layer on top of a doublet. Top layer may consist of clear quartz, glass or hard plastic material. This is used to thicken and give additional strength to the item.
Updated on 10/26/17