Cornwallstone

Cornwallstone is a low iron feldspar material used primarily as a flux in clay bodies and glazes.  It melts 1150-1300C.  It has a more diversified selection of fluxes than other feldspars but also has one of the highest silica contents.  It is popular in engobes for its adhesive power during and after firing and in glazes for its low shrinkage and minimal contribution to defects.