Minspar 250 Feldspar (NC4)
This is the old NC-4 soda spar. Soda feldspars, the second most common form of feldspar, are used as a body flux and in glazes they provide silicates. Slightly different color developments will occur if sodium feldspars are used in place of potash ones due to the difference in alkaline properties. Sodium feldspars have a high coefficient of expansion and glazes that contain them are more likely to craze. Larger amounts are available. Please call the store for quotes.