This tile has firstly an iron earthenware glaze (1150) under with the Cover Cote glaze from this page over it. It will pool nicely, not too thick on the upright. A real nice effect though , there are rust tenmoku parts in the brown sections. This was on porcelain. cone 6 electric.
This effect was done cone 05/06 in a bisc kiln.Underneth i put a low temp iron glaze as in any raku glaze with 9-10 % iron with a lichen glaze over it.- Borax-27% /mag.carb 33% / Ger.borate- 33% / Silica 7% / Zircopax -7% Glaze from B.Sabin.
This is the GA27 glaze as above but put over the iron under cote from the oil spot glaze on this page.This gives a dark brown to black that has life in it as the iron bleeds thru. from the under cote, so other possibilities are there as in a red stain added to the under glaze? cone 6 electec