Crystalline Glazes

My interest in crystalline glazes began about six years ago (in 2013) during my last semester at Alfred University. I was only vaguely familiar with these glazes, in which minerals crystallise within the thin layer of glaze coating a ceramic piece. I had heard it was possible to grow agate-like rings in the crystals, which I thought would look cool on the abstract leaf sculptures I was making at the time, and fitting as they can grow like tree-rings which grow outwards and respond to changes in temperature.

After my first batch of glaze tests it was clear that it would take a lot of work to get the glaze result like I had pictured in my mind, but I was fascinated by the results and quickly became pretty obsessed. The months leading up to graduating from college I was firing their little .5 cubic foot test kilns everday, sometimes more. After graduating getting a similar little test kiln was one of the first things I did.

Six years later I’m still very interested in these glazes, and regularly firing kiln loads of test tiles. I’m especially interested in getting different minerals to crystallise. I can reliably get Willemite, Titanite, and Hematite to form within the roughly 2,000 Fahrenheit molten glaze. Along with a couple of crystals that I haven’t been able to identify.

I now mostly use glazes that fire to cone 5, with over 20% Kaolin which helps them to not run too much, not craze too much, and be more durable. And I stubbornly refuse to use any glazes which I haven’t personally formulated, tested and mixed.