Table Of Gemstone Treatments

Gemstone Form of Treatment Frequency Reason for Treatment
Amethyst Heating Occasional To lighten color and/or remove smokiness.
Aquamarine Heating Routine To remove yellow in order to produce a purer blue color.
Beryl Irradiation Routine To create blues and yellows from colorless stones.
Diamond Laser Drilling
Fracture Filling
Irradiation
HPHT
Coating
Occasional
Occasional
Routine
Occasional
Occasional
To bleach out dark inclusions.
Filled with chemicals sharing the same refractive index of diamonds.
To make existing colors more intense or induce new colors.
To change brown diamonds to whites, yellows, greens and some pinks.Can make all colors but primarily used to make pinks
Emerald Oiling
Impregnation
Routine
Occasional
Colorless oil is used to penetrate into surface reaching fractures making them less noticeable.
High-grade epoxy resins can be used to fill the surface reaching fractures to make them seem less noticeable.
Jade Bleaching
Impregnation
Dyeing
Occasional
Occasional
Occasional
To remove any dark discoloration.
With colorless wax, to improve appearance.
To imitate natural colors.
Opal Assembledproduct
Impregnation
Routine
Routine
Usually opal doublets can be made by combining via epoxy, a thin layer of opal backed by either chalcedony or boulder rock.
Impregnated with colorless resins and hardeners.
Pearl Bleaching
Dyeing
Irradiation
Routine
Routine
Occasional
To remove discoloration.
To improve color.
Certain pearls can be subjected to irradiation to permanently alter their color to gray, black or blue.
Quartz Heating Routine To improve color.
Ruby Heating
Cavity Filling
Diffusion
Routine
Occasional
Routine
To intensify or lighten color.
Surface cavities are filled with foreign material (sometimes glass).
To produce an artificial star on a natural stone.
Sapphire Heating
Diffusion
Irradiation
Routine
Routine
Occasional
To intensify or lighten color.
To produce an artificial star on a natural stone.
To obtain yellow or orange color from colorless stone.
Tanzanite Heating Routine To produce the violet-blue color for which the stone is known.
Topaz Irradiation
Heating
Routine
Routine
To create blue, yellow and green topaz.
To create pink or red topaz.
Tourmaline Heating
IrradiationCavity
Filling
Routine
Occasional
Occasional
To improve intensity for blue-green colors.
To intensify pink, purple and red colors; blue tourmaline can be irradiated to purple.
Hardened colorless substances are often used to fill cavity.
Zircon Heating Routine Brown zircon is heated to make red, blue and white zircon.