China's sapphire is best in Shandong (Chang Le) sapphire. The crystal is hexagonal in shape and has a large particle size, generally above 25px, and up to several thousand carats. Sapphire is mostly indigo, blue, green and yellow near carbon black due to its high iron content. Mainly indigo. There are very few inclusions in gem-quality sapphires. In addition to the black solid inclusions, fingerprint-like inclusions are still visible. There are no silky rutile and diffuse liquid inclusions. The flat ribbon in the sapphire is obvious, and the polycrystalline twin crystal is not developed. The outer edge of the large crystal can be seen as a growth line parallel to the hexagonal cylinder. Shandong sapphire is a high quality sapphire because of its internal defects. Doup Wire,Leno Doup Healds,Doup For Weaving Machinery,Plastic Doup Heald Transally weaving accessories Co., Ltd , https://www.transally-co.com