Some would say that real glazed ware must contain lead. However, now that everyone worries about this dangerous heavy metal soaking into food cooked in lead-containing pottery, most vendors swear that their glazed pottery contains no lead. Lead poisoning is such a serious matter that I'm not sure what to advise if an extremely lustrous pot catches your fancy. Stoneware is pottery made of high-silica clay, which when fired becomes particularly hard and impervious to liquids. The term graniteware can be used for pottery made of high-silica clay that is light colored and coated with a glassy, or vitreous, glaze traditionally containing lead.
Porcelain is the most delicate type of pottery.
It is made of kaolin, a very fine-grained, white clay, and is not produced by traditional Mexican artisans. Among Mexican towns producing the finest pottery are Tonal and Tlaquepaque near Guadalajara. In Michoac n, near P tzcuaro Lake, the ancient capital of the Tarascan Indians, Tzintzuntzan, still produces superb traditional pottery. In Oaxaca, in the town of San Bartolo Coyotepec, about six miles south of Oaxaca City on Mexico 175, a famous black pottery is available in both glazed and unglazed forms. A similarly fine, green, glazed pottery comes from Santa Mar a Atzompa, on a small road just west of Oaxaca City.