jade, jadeite, fei cui, Japan, gems

Even though Japanese jadeite lacks the transparency of the highest-quality Burmese imperial jadeite, its rarity and natural features make it a highly valued gemstone. In this study, jadeite from the Itoigawa and Ōmi regions in Niigata Prefecture and the Wakasa region in Tottori Prefecture, both on Japan’s western coast, were divided into several color varieties corresponding to chromophores and mineral phases: white (nearly pure jadeite), green (Fe-rich, Cr-bearing), lavender (Ti-bearing), blue (Ti- and Fe-bearing), and black (graphite-bearing). White jadeite from Itoigawa–Ōmi was close to pure jadeite (Xⱼd = 98, or 98% jadeite composition). Green jadeite from the same location had an Xⱼd range from 98 to 82. The maximum CaO content in green jadeite was 5 wt.%, and its chromophores were Fe and Cr. Whereas lavender samples had a jadeite composition of Xⱼd = 98 to 93 and tended to be high in TiO₂ and FeOₜₒₜ and low in MnO content, blue jadeite showed the highest TiO₂ concentration at 0.65 wt.% and had an Xⱼd range of 97 to 93. A blue jadeite from Wakasa had a range of 97 to 91 and a similarly high TiO₂ concentration. In trace-element analysis, chondrite-normalized and primitive mantle–normalized patterns in lavender, violetish blue, and blue jadeite from Japan showed higher large-ion lithophile element contents (Sr, Ba) and higher field strength element contents (Zr, Nb) than those in green jadeite, while white and black jadeite had relatively low REE contents. The Japanese jadeites were compared to samples from Myanmar, Guatemala, and Russia.