DH, this really is a puzzle. Thank you for sharing all your info with us. I have only used the Turq matte as an overspray with other colors. I think I may do a little testing myself. But like Min said, perhaps it is a bad batch of clay? I think that happens? I had a couple of boxes from Aardvark that had rocks in it. Is it possible to get a different clay and try the same glaze combo?