... 3 days without changing, 2.Yixing clay Teapot (Purple clay teapot ) surface with very beautiful shape, ... artistic culture Sientific Prove3.Yixing clay Teapot (Purple clay teapot ) is a rare earth, from ... scientific research, purple clay does not contain lead, arsenic, cadmium, ... to human healthy, whereas the research proves that purple clay contains SiO2, Al2O3, Fe2O3, MgO, CaO ...