Precious Stones Certificates
A Coloured Gemstones Certificate gives the owner or buyer of stone the possibility to know whether it has been enhanced in any form, such as by heat as might be the case with rubies and sapphires, or oiled if dealing with an emerald. It may also disclose whether a gem has been altered or visually improved in any other way including using a foreign substance. A certificate further provides basic details on the stone such as its dimensions, its approximate colour grade and possibly its origin, if identifiable and requested. It thus also provides ample information towards ensuring a sound appraisal.
The most internationally renowned coloured gemstone certificates are issued by the SSEF (Schweizerische Stiftung für Edelstein-Forschung), particularly great for origin determination, and the equally scientifically stringent AGL (American Gemological Laboratories). They are followed by Gübelin which remains greatly appreciated in Asia at present. GRS – GemResearch Swisslab is another commonly used Gemological Laboratory. Other slightly lesser known but nonetheless respected labs, sometimes newcomers, include DSEF (Deutsche Stiftung Edelsteinforschung in Idar-Oberstein), CGL (Carat Gem Lab), Christian Dunaigre and for Rubies, Sapphires and Spinel specifically Lotus Gemology of Bangkok, Thailand, headed by expert Richard Hughes. Some of the smaller labs remain particularly popular as first or second opinions or to certify lesser stones as the costs for the major certificates may be considerable.
Buyers of Important or Investment grade precious stones should always make sure such gems are accompanied by at least two or preferably three certs preferably pertaining to the most respected labs: SSEF, AGL and Gübelin. This is done in order to obtain unanimous results which remove any doubts and drastically improve marketability.