Crystalline glazes are mesmerizing to observe.  Some look like ice crystals on a window in the winter and others have been described as ginkgo leaves.  The glazes seem to be much like a hologram when held under light.  The crystals are zinc silicate crystals that form inside of the glaze due to the glaze ingredients and the firing schedule in the kiln.  My firing schedules range anywhere from 16 to 24 hours long depending on the glaze I am using.  This process requires keeping very accurate notes and records to repeat your results each and every firing. These glazes are very, very finicky and one small alteration to a variable can ruin an entire load.

The process involves a glaze that is high in zinc and silica content and lacking in alumina which causes it to be a very fluid glaze.  Because of this, much of the glaze runs off of the piece during the firing. This requires a catcher plate and specially designed pedestal for each crystalline pot to be mounted to prior to firing.  My firing schedules take the crystalline pots to a peak temperature between 2300 and 2490 degrees Fahrenheit where they are held for a short period of time.  They are then quickly dropped to a crystal growing temperatures which are within the range of 1820 and 2100 degrees Fahrenheit for my glazes.  The pots may be held for many hours at one or many temperatures within this growing range to get different effects from the crystals.