Gemmological and Mineralogical Characteristics of Nephrite Containing Pink or Red Minerals

Recently, nephrite containing pink or red minerals has appeared on the market, the former is called "Cherry Blossom Pink", and the latter is called "Carmine". For nephrite containing pink minerals, some researchers suggested that the pink colour may be caused by Mn-bearing epidote, and some agreed that it might be caused by Mn-bearing zoisite. At present, no report can be found on nephrite containing red minerals. In this study, conventional gemmological test instruments, Raman spectroscopy, scanning electron microscope, UV-Vis spectroscopy and laser ablation inductively coupled plasma mass spectroscopy (LA-ICP-MS) were used to investigate the mineral components and colour origin of these two kinds of nephrite. The results showed that the colouring minerals in these kinds of nephrite samples are Mn³⁺-bearing zoisite(pink) and Mn³⁺-bearing clinozoisite(red), respectively, and their colours were mainly caused by the d-d transition of Mn³⁺ at the M3 site. By Raman spectroscopy, two minor minerals, nesquehonite and native sulphur, were found in the nephrite containing red minerals for the first time.