gems, jade, pyroxene jade, fei cui, jadeite, dyed jade, treated jade, composite jade, plastic-coated jade

We have commented on the variable fastness of the colors used in dyeing jadeite. We recently tested some dyed stones of excellent color. The owner stated that he had purchased them in 1955—a full year before we first encountered the stones in the course of our testing work. He further stated that to his recollection they had not faded. In another note, a necklace of round jade beads showed the treated spectrum and the normal jadeite absorption line at approximately 4370 Å, but the refractive index was approximately 1.55 by the spot method. Magnification revealed that the stones were plastic coated, in addition to being dyed; hence, the “wrong” refractive index for jadeite. And another note: Figure 3 illustrates a small, flat, oval cabochon of jadeite, one of a group that a manufacturer stated had altered radically in appearance following normal steam cleaning of finished jewelry. What had originally been evenly colored medium-green stones became mottled with numerous white, intersecting cracks. The only suggestion we could offer was that perhaps the stones had been oiled to camouflage the cracks before they reached the manufacturer.