Treatment/ Enhancement Codes and what they mean

Here is a "legend" or "key" to help you understand what the gemstone treatment section stands for.

Gemstone Enhancement Codes*

N = Not Enhanced B = Bleaching C = Coating D = Dyeing F = Filling H = Heating

HP = Heat & Pressure I = Impregnation L = Lasering O = Oiling/Resin R = Irradiation

U = Diffusion SC = Special Care ASBL = Assembled CMP = Composite

W = Waxing/Oiling in Opaque Stones

*Codes and type of treatments must only be used as directed in the Gemstone Information Manual, available at

These will help you understand more about how we grade the gemstones on our website. Please let us know if you have any questions.


The Gem SyndicateThe Vault

We’re selectively social

Follow us to learn more about our journey.

20% Off Your First Order

Join The Gem Syndicate email list for sales and new product drops + 20% off your first order.
No Thank You