Ranging from a dark blue-green to white and powder blue. At times, this glaze also has a slight iridescence. Crystal rings range from a silvery blue to a lavendar blue, reminescent of Amethyst. This color is primarily the result of Cobalt.

This glaze is named Phil’s Blue after Phil Hamling, the ceramic engineer who taught Andy to work with crystalline glazes. It was the first glaze Andy began working with and has only small alterations from the original recipe that Phil had been working with. Phil had gotten the idea for this glaze based on the work of Ian Childers, a very talented crystalline glaze artist.