The magic of this recipe is the 5% extra frit, that makes the melt more fluid and brilliant and gives the glaze more transparency where it is thinner on edges and contours. The extra iron in the Plainsman P380 (right) intensifies the green glaze color (vs. Polar Ice on the left).
The specks are cobalt oxide agglomerates that were made by slurrying cobalt oxide and bentonite, then crushing it to sizes large enough to make the specks.
GR6-N - Ravenscrag Alberta Brilliant Cone 6 Celadon
Plainsman Cone 6 Ravenscrag Slip based glaze. It can be found among others at http://ravenscrag.com.
A type of stoneware glaze normally fired in a high temperature reduction atmosphere kiln. It is transparent and stained green or blue by the presence of iron oxide.