Not exactly Oil Spots in the truest sense, these two variations were concocted and tested along with the rest of my oilspots glazes. Both of these recipes utilize some local dolomitic limestone I found and incorporated into the recipes. If you want to re-create these, using a mix of 1/2 and 1/2 Dolomite and Limestone will get you very close.
The first variation is based off a line blend [ 1 part Limestone : 1 part silica : 4 parts feldspar] This, by the way, is a pretty good starting point for a cone 10 glaze if you’ve got any, or all of those prospected materials around you. This variation also has 1% Cobalt, 6% Iron, and 3% Manganese.
The next variation started with the same rough ratio and upped the Manganese and Iron significantly. Pretty interesting variation, too. It’s much closer to my Iridescent family of glazes than it is to my Oilspots.