I-Minerals states that they are "focusing on potassium feldspar (K-spar). Deposits of high quality K-spar that can be economically extracted are rare. This rarity of quality deposits has resulted in K-spar selling at much higher prices than sodium feldspar. At present there is no domestic U.S. production of K-spar with K2O purities in excess of 10.0%. I-Minerals is developing a series of K-spar products under the Fortispar TM branding in the 12.5% to 13% K20 range. Fortispar products will be offered in 200, 325 and 635 mesh grinds to meet the requirements of a given industry."
Fortispar is a high quality potassium/sodium/calcium aluminum silicate used as a source of alumina and potash in ceramic, paint, and other
applications. Carefully beneficiated using the froth flotation process, Fortispar™ K offers low iron oxide and high alkali oxide content per unit of alumina.