I had a new glaze variation in my last kiln firing!
Not sure exactly where I came across this formula, so apologies for the lack of attribution, but here it is in case anyone else wants to play with it:
Cone six, opaque matte.
34 nepheline syenite
7 calcium carb
5 zinc oxide
The original recipe says to add 2 bentonite, 0.5 copper carb, and 1 cobalt carb. I’ve never actually seen what that looks like; the pieces up there have 2 bentonite and 1 copper carb, which gives that greenish greyish not-quite turquoise. The only other version I’ve tried had 2 bentonite, 0.5 cobalt, and 1 copper carb, and that gave a very muted, greyish blue that could go very slightly bright sky blue where it pooled.
I discovered it crawls like crazy if you apply it thick with my clear over top, but that’s not unusual. I’ll just slap it on thinner next time.