crack or hairline

[marV]

First crack was break thru entire piece after about one week. The other breaks were also all the way thru – those didn’t happen until about two weeks later. The entire fused and slumped piece was about 1/4′ thick when done. Begain with one piece opaque white and another layer of opaque pieces along with transparent blue and a few black stringers. I can only think that it was caused by improper anealing or cooling. The piece was at room temperature when I took it out of the kiln the next day. I did take it out of the mold and left it on a shelf in the room. It remained then for about one week when I noticed the first crack. I then put it into the mold to see if there would be any way for it to be fit together if I refired it. The two pieces would not have easily fit together so I just left it in the mold.