I did not want the above post to get too complex so here is even further information regarding disclosure of "treatments". Most stone we use falls into this category:
ornamental stones (5.39). Note all of the disclose requirements specifically do not apply to:
ornamental stones (5.39). ATGA - American Gem Trade Association
D.Merchandise must not be misrepresented as to its nature, authenticity, treatment and/or origin. Disclosure of treatment is mandatory on all commercial documents for each individual stone and/or lot at the point of consignment or sale, and must be in accordance with the Gemstone Enhancement Manual,
as long as the requirements therein are not contrary to those of the Federal Trade Commission.
Quotes from handbook –
“To improve its color and durability, turquoise is commonly permeated with plastic, a stable enhancement.”
2012-12-30 CIBJO/Coloured Stone Commission
http://www.cibjo.org/download/13-03-19%20Official%20CIBJO%20Gemstone%20Book-2.pdfNOTE - CIBJO recognizes that its standards are subject to government regulations in the respective jurisdiction of CIBJO members.
4.1.3 . Modified gemstones and organic substances
Precious stones (5.41), gemstones (5.25),
ornamental stones (5.39) and organic substances (5.38) are often modified (5.33) by various processes, before and/or after cutting, to improve their colour or clarity.
There are two categories of modified gemstones and organic substances: Gemstones and organic substances requiring general information of their modifications (4.1.3.1), and: gemstones and organic substances requiring specific information (4.1.3.2) of their modifications
4.1.3.1 Gemstones and organic substances requiring general information on their modifications
Gemstones and organic substances requiring general information on their modifications include those listed in clauses 4.1.3.1.1 to 4.1.3.1.4 only.
4.1.3.1.1 . Substances present in fissures that do not add colour
Gemstones (5.25) and organic substances (5.38) modified by the presence within fissures (5.20) of agents such as oil, wax, resin, polymer or any substances, other than glass that do not add colour to the gemstone or organic substance, when viewed at 10 power magnification by a trained observer.
4.1.3.1.2 . Surface waxing
Gemstones (5.25) and organic substances (5.38) modified superficially with a colourless agent such as oil, wax, organic fluid or polymer.
4.1.3.1.3 . Heating.
Gemstones (5.25) and organic substances (5.38) permanently modified by heating
COLOURED STONE COMMISSION 2012-1
© CIBJO 2012. All rights reserved.
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(5.27).
NOTE – A gemstone and organic substances may still be classified in this category when residues from the heating process are present within healed fissures. However, when healed fissures are polished flush with the surface of the stone, the residues should not be visible by having a different polished surface lustre to the host material, when viewed at 10 power magnification by a trained observer.
4.1.3.1.4 . Bleaching
Gemstones (5.25) and organic substances (5.38), other than pearls and cultured pearls, modified by bleaching (5.8).