2. Obsidian Tianmu Tea Bowl: The Song Dynasty (east of Jian 'an County, Jianning Prefecture, now belonging to Jianyang District, Nanping City) was built with black glaze, which was used by Song people to fight tea. The Japanese used the word "the universe in the bowl" to describe this bowl, saying that it seemed to be the starry sky seen by the beach at night, which was unfathomable.
3. Black glazed oil drop bowl: one of the national treasures of Shaanxi History Museum. The glazed bowl is small in mouth and gray in fetal quality, and it is covered with black glaze. The surface of oil layer is covered with small spots of different sizes, which is called metallic luster. These dots are like oil drops floating on the water, so they are called "oil drop glaze". Oil drop glaze is a special kind of glaze, belonging to crystalline glaze, which is the largest glaze of its kind seen so far.