K9 crystal is an optical borosilicate crown glass crystal that is manufactured in China. It features exceptional physical properties and can easily be polished like any other leaded glass.
K9 crystal glass is relatively lighter and cheaper compared to other glass crystals. Its low production cost, low-dispersal properties, high refractive index and high clarity makes it a good option for making the prism and lenses used for optics and lasers. K9 is also used to make high end chandeliers. Products made from K9 are quite popular because they offer both durability and high quality at a reasonable price. The use equivalent of K9 is BK7.