The 3 Cs of Natural Precious Opal
September 2011
In late May 2011, Opal Horizon Limited presented its "3Cs of Natural Precious Opal" classification and grading scheme at the Gemological Institute of America Symposium in California. This scheme has been reported on in the World trade press as follows:
Jeweller Magazine (Australia)
Uhren Juwelen Schmuck (Germany)
Bilckpunkt Juwelier (Germany)
Canadian Jewellery Magazine (Canada)
Gold Magazine (Spain)
Goldsmith Magazine (Great Britain & Europe)
National Jeweler (USA)
Orion (France)
Le Bijoutier (France)