WATCH OUT FOR TREATMENTS
Treatments that won’t affect the transparency of the stone, such as waxing, are acceptable, but heavy enhancements and the introduction of foreign materials and dye devalue the stone. Chow says that buyers must look out for resin-treated stones or concave cabochons, as these have undergone processes to remove defects or artificially improve translucency.
In laboratory reports, jadeite is classified as Type A, B or C. Type A refers to a stone that has been waxed but undergone no chemical treatment. Type B jadeite has been impregnated with a synthetic substance to enhance translucency. Type C refers to a stone that is usually colourless or of very faint tone that has been artificially dyed to enhance its saturation—an enhancement that will fade with time. With Type A jadeite commanding some of the highest prices of gems today, Chow says it’s always worth paying for an independent report to confirm that what you are buying is genuine. Auction houses such as Bonhams ensure each piece comes with a lab report from an independent agency.