Ingredients

Ingredient Amount
Gerstley Borate 2.90
Ferro Frit 3124 8.80
Magnesium Carbonate 2.90
Whiting 22.40
Nepheline Syenite 22.70
EPK Kaolin 20.30
Silica 20.00
Add Amount
Copper Carbonate 4.00
Cobalt Carbonate 3.00

Instructions

Published in "Firing Up and Down" by Deanna Ranlett, in the Jan/Feb 2014 issue of Pottery Making Illustrated.
For a lighter version with a microcrystal surface, fire down 500°F per hour to 1900°F, then 125–175°F per hour to 1450°F (use your glaze results to find the exact drop right for you), then allow the kiln to cool naturally from there down to room temperature.