Liuli or Colored Glaze, was the term used to describe glass during the Chinese Tang Dynasty. The art work is made from a combination of glass and lead dioxide. While the proportion for mixing glass and lead dioxide differs from country to country, generally speaking, when the percentage of lead dioxide reaches 24% and above, the translucency and refractive quality of the glass reaches an excellent level. At the same time, the crystal glass is also heavier, softer and in prime condition for crafting into fine works of art. Liuli is well-known for their high quality comparable to European and American crystal glass products and is thus superior in price and quality to ordinary glass products.