Minspar (formerly called NC-4) is a sodium rich feldspar mined in Spruce Pines, NC. It is used in clay bodies to promote vitrification and in cone 6-10 glazes as an inexpensive glass-former. Nepheline syenite, a silica poor cousin, can be used as a substitute (replace 100g Minspar 200 with 75 g nepheline syenite + 25 g. silica).
For more information on Minspar feldspar, see the Digitalfire.com Reference Library of ceramic materials.
Different Raw Materials ordered in full bag qty (20 kg to 100 lb) will be combined at checkout for a volume discount if applicable.