| Abstract: | the paper has systematically set forth the existed different naming and identifying methods for gem's colour. Among the naming methods,they are:double naming, simi-lary method, saturation method and three elements method while among identifying methods, they are; visual measurement, instrument measurement and comparative method. And the paper has also pointed out that they all have a few shortcomings in different degrees. However, relatively speaking, comparative method by using colour spectrum system is the better one up to now. |
