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Gem treatment symbols:
ASBL Assembled from pieces of the stated material(s) along with binders, substrates, caps, or carriers. B Bleached. C Coated. D Dyed. F Cracks & crevices filled with a fairly durable material. H Heated. HP Heated under pressure. I (same as S). IMIT Imitation – a manmade, or (usually treated) natural, material designed to resemble the stated stone but not equivalent to it chemically and physically. L Lasered, possibly with chemical treatment. MM A manmade material having no natural equivalent. (Such materials are often not marked with this symbol if the very name of the material designates a material that is generally known to the trade to be manmade). N Natural. This symbol is used either to emphasize that a material that the reader may imagine to be treated, is in this case untreated; or to designate that a stone that has a gemologically inaccurate colloquial name is in fact an untreated stone although not the stone the name suggests, e.g., undyed mountain “jade”. O Oil, resin, or wax colorless infusion, usually in the context of a transparent stone penetrated by tiny voids that would otherwise be conspicuous, e.g. emeralds. R Irradiated and possibly heated. S Stabilized (impregnated with a resin usually suitable for subsequent cutting and polishing). SYN Synthetic (laboratory duplicate of the natural stone, having its same chemistry and crystallography.) U Chemicals diffused into surface under high temperature. W Colorlessly waxed or oiled, usually in the context of a nontransparent stone. |