I first learned about crystalline glazes in a ceramics class with Kerra Kinion at TMCC (Truckee Meadows Community College). With Kerra’s help, a few of us experimented with crystalline glazes.

I was hooked! Even with all the challenges, I loved the crystals and their unique patterns.

After numerous experiments with different formulas and temperature ranges, I settled on this base glaze with colorants added to create different crystals.

I’ve not tested this formula for food safety. So I consider them NOT food safe.

As always wear protective gear when handling any chemicals. Usually this includes a respirator and gloves.

Base Glaze

Frit 3110 540g 52.3%
Zinc Oxide (506xx) 270g 26%
Silica 198g 19.2%
EPK 25 g 25%
Total Weight 1033g 100%

Colorants

Black Background with Blue Crystals
Manganese 3%
Black Iron Oxide 3%
Cobalt Carbonate 3%

Brown Background with Blue Crystals
Nickel Oxide 0.5%
Black Iron Oxide 1.5%
Manganese 1.5%

Blue Background with Silver Crystals
Nickel Oxide 0.4%

Warning! During firing these glazes RUN like crazy.

I’ve provided a few resources that can better describe the forms best suited for these glazes.

Resources

‘Crystalline Glazes’ by Diane Creber
‘Glazes for Special Effects’ by Herbert H. Sanders (out of print, but may find in library)
“Making and Firing Crystalline Glazes’ by David Snair, Ceramics Monthly, December 1975