Different teapots have different characteristics, for instance silver is especially suited for slow cooking aged teas (eg pu'er, dark tea) to activate their original flavour. Golden teapots are mainly kept as crafts for display or collection and are seldom used to boil water due to the fast dissipation of heat which could affect the tea's flavour. Iron teapots, regarded as symbols for Chinese culture, are the best choice for boiling water as they can help release the tea's flavour and fragrance, and can soften the water and improve its taste.