By Branko Deljanin
Jade is a commercial term encompassing green, white, black, and yellow-brown jadeite and nephrite. The world nephrite jade market is estimated at more than 1000 tonnes per year, with half the supply originating from British Columbia. Just as Canadian diamonds are a source of national pride, the same is true of Canadian jade. Yet, with only 20 per cent of the material mined of gem quality, misrepresentation and non-disclosure are very real possibilities.
At the GJX show in Tucson earlier this year, World Gem Society (WGS) president Robert James reported some Chinese dealers selling what they called ‘Canadian Jade’ (Figure 1). This material was said to be virtually identical to known Canadian nephrite jade. A closer look under a 10x microscope, however, revealed it to be dyed quartzite (Figure 2, page 2). At a fraction of the cost of true Canadian jade, it won’t be long before this material makes its way through the supply chain in large quantities.
Last year at our lab in Vancouver, we received a necklace of green beads for testing (Figure 3, page 2). Our client bought it believing it was natural jadeite jade, and wanted an appraisal for insurance purposes. The colour looked good and visually, it appeared to belong to the jade family—it had a very high translucency usually associated only with the highest-quality jade.
Upon closer examination, we noticed a concentration of colour around the grains. We also found it had a low spot refractive index (RI) of 1.55. (Nephrite jade’s RI is 1.61, while jadeite jade’s is 1.66). We informed the client the gemstone was not jade, but rather dyed quartzite. As you can imagine, he did not return to pick up the necklace, and we now use it as an example in our lectures and training workshops.
With what might be an influx of Chinese ‘Canadian jade’ hitting the market, an overview of natural jade’s properties may be in order.