Small thrown bowl made from pure #6 Tile kaolin. It is fired to cone 6. This type of surface cracking happens during the firing, it is typical when trying to fire a pure kaolin (it needs a filler). While this specific kaolin throws well all by itself, most are far less plastic. Pure kaolins are also refractory, so the porosity of this piece is very high, completely impractical for functional ware (it needs a flux like feldspar).