蓝宝石       Sapphire

蓝宝石的化学成分为（），因含微量元素钛（Ti⁴⁺）或铁（Fe²⁺）而呈蓝色。透明度为透明至半透明，并带有玻璃。为1.76-1.77，双折射率0.008. 硬度为9，3.95-4.1克/立方厘米。实际上自然界中的宝石级刚玉除红色的称外，其余各种颜色如蓝色、淡蓝色、绿色、黄色、粉色、灰色等，均称为蓝宝石。世界蓝宝石产地不多，主要有、、、、等，但就宝石品质而言，以缅甸、斯里兰卡品质最佳。

The chemical composition of Sapphire is Al₂O₃.The color is blue due to trace elements of titanium (Ti⁴⁺) or iron (Fe²⁺).Transparence of Sapphire is transparent to translucent, and has glass luster. Refractive index is 1.76-1.77, double index is 0.008-0.010.The hardness of Sapphire is 9,density is 3.95-4.10 g/cm³.Actually,all kinds color of Sapphire in the nature like blue, light blue, green, yellow, pink, and gray, are known as Sapphire. There are not so many original place of Sapphire in the world. The main places are Myanmar, Sri Lanka, Thailand, Australia, and China. The best quality Sapphire are from Myanmar and Sri Lanka.