It belongs to a siltstone, which contains of iron, quartz, and mica as its main minerals, precise modeling for teapots.

• 紫砂陶土质细致，泥坯靭度极高，为一种含铁质粉砂岩，由石英，云母，铁质等矿物成分构成，宜于制作精巧的茶壶。