Bert I use a Primo pizza stone that came glazed on one side. I applied a food safe glazed onto the otherside. The reason I did this is because the stone is quite porous and I didn't want oils seeping into the stone which would be another benefit. But yes, glazed stones or the process of glazing it yourself can be considered expensive. IIRC, the added cost to glazing several stones was something like $25-$30 extra.