Testing

 
Sydney has this vast store of ceramic materials (alongside his massive stocks of bricks,his extensive kiln-shelf collection and his stockpiles of unobtainable local clays),some of questionable identity- he showed me this test tile,for instance,of something he was pretty sure was alumina,fired alongside some real alumina- looks like the stuff on the right is more likely something in the feldspar family.We had a good laugh.