Old mud, new mud is the majority of friends have a misunderstanding. In fact, the formation of Yixing today is through tens of millions or billions of years of time, can be said to be old mud. As for the mud weathering period, but the length of stale period. Purple is formed through hundreds of millions of years, the so-called new old mud mud, just in the stale period difference only. The mud stale period to some extent is as long as possible, but in the pot before back out. The time of mud mud with stale stale period short to Zhi Qiao plasticity, a little higher. Feel not so console. Prepared a pot of water, is ugly. A color, better.