The following chart explains the enhancements and treatment codes that you will see on our website. They are derived from
industry standard codes which we have amended for further clarification.
- N = Natural (No enhancement)
Gems that are, according to best available information, untreated.
- H = Heat only
Enhancement via heat only.
- U = Diffusion
Enhancement by the diffusion of foreign elements into the crystal lattice of a gemstone. Example: Beryllium-diffusion.
- HP = Heat & Pressure
Enhancement via extreme heat and pressure. Also referred to in the industry as HPHT (
- F = Filling
Enhancement by filling a gemstone's cracks and crevices with a
- FD - Filling & Dye
Enhancement by filling cracks and crevices with a
- D = Dyeing
Enhancement by the introduction of a
- IR = Irradiation
- TPL = Triplet
To add a clear protective layer on top of a Doublet. The top layer may consist of clear quartz, glass or hard plastic material. This is used to thicken and give additional strength to the item.
- C = Coating
Enhancement by the application of an artificial layer to the surface.
- B = Bleaching
Enhancement by heat, light, and/or chemical agents to lighten or remove
- O = Oiling
Enhancement by bathing the gemstone in
- R = Reconstruction
Enhancement by use of heat, pressure, and/or solvents to fuse small pieces of a gem together into a larger whole. Often used in
- I = Impregnation
Enhancement by melted wax or plastic forming a layer over the surface of a gemstone to improve
- A = Assembled
Enhancement by assembling other substances over or under a gemstone to improve durability and size.
- S = Smoking
Enhancement by smoking a gemstone and replacing its water content with carbon. Sometimes the smoke can be dyed.
- DBL = Doublet
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.
- HTLE = Heat and Light Elements
Enhancement by adding a chemical element during the heating process of a gemstone.