Spirits in the Wind Gallery unveils New Functional Art Stoneware in Varied Colors. Platters, bowls, mugs and more.. We are so excited to welcome K. Brooks. ?Crackle glass ceramics? pieces are jaw-dropping stunning and functional. Before putting each piece in the kiln to fire the glaze, artist adds wax and crushed glass to the center of the piece. The wax and glass both melt in the kiln, the wax evaporates, and the glass crackles as it cools and solidifies.