The sapphire which occurred in basalt is generally with dark color. Due to huge crystal, Changle sapphires apperar to be darker. Many experiments on changing colors of Changle sapphires have been carried out, but the effect not obvious. By the analysis of results obtained from electron microprobe and ultravalet-visible spectrum-near infrared absorption spectrum sketch, and the relation study between colors and chemical compositions, some recongnizations have been got as following:major color-causing element...