A jade triplet is a composite stone construction in which a thin slice of natural jadeite (typically a low-saturation green or near-colourless material with good translucency) is mounted as the upper layer of a cabochon, bonded with a coloured (usually green) cement layer to a lower layer of jadeite, quartz or glass. The intent is to imitate the appearance of fine imperial-green jadeite while using only a small quantity of the higher-grade material, with the body of the cabochon made up of cheaper substrates and the colour generated by the central cement layer.

Construction

The standard jade triplet has three layers. The top is a thin (typically 1 to 3 mm) slice of natural pale or colourless jadeite, sometimes specifically of the more translucent "icy" type, polished to the finished cabochon's upper curve. The middle is a layer of dyed adhesive, traditionally a green-tinted shellac or, in modern work, a coloured epoxy resin. The bottom is a thicker piece of jadeite, white quartz, chalcedony or in the cheapest constructions glass, polished to the finished cabochon's lower curve. The three layers are bonded under pressure and the assembled cabochon is conventionally mounted in a closed-back setting that conceals the base and the joins.

Detection

Triplets are usually detectable by examination at ten- to twenty-power magnification along the girdle, where the joins between layers are visible as straight lines or seams running around the equator of the cabochon. Immersion in a refractive-index liquid (such as methylene iodide for jade, RI around 1.74) often makes the seams more visible. Coloured-filter examination shows that the green colour is concentrated in a thin central plane rather than dispersed through the body of the stone. Long-wave ultraviolet fluorescence may show different responses from the upper and lower layers. Closed-back mountings make detection difficult without unmounting, and laboratory testing (typically by FTIR and microscopic examination) is the conclusive method.

Trade context

Triplets have been used in the Hong Kong and Bangkok trade since at least the early twentieth century and remain a periodic problem in the wholesale and retail jade markets, particularly in the lower price brackets. The principal modern concern is not the triplet itself, which is a recognised composite category requiring disclosure under CIBJO and national codes, but undisclosed triplets sold as solid jadeite. Reputable trade practice requires open-back mountings for jadeite cabochons over a meaningful price threshold, both to permit examination and as a market signal of confidence.