A specific type of high-iron glacial clay found near Albany, New York, used extensively as a dark, glossy brown glaze on stoneware. Because it acts as both a slip and a glaze, it requires no additional fluxes to melt at high firing temperatures. The original mine closed, so potters use synthetic substitutes made from local clays mixed with iron and fluxes to replicate its reliable, self-glazing properties.
Heard on the job
We're out of the true Albany slip, so mix up a batch of the synthetic substitute for the stoneware jugs.
Insider tip
True Albany slip is no longer mined, making authentic dry stock highly prized among traditional stoneware potters.