http://www.ec21.com/ec-market/k-feldspar.html http://mayally.en.ec21.com/Potash_Feldspar--3844050_3844108.htmlK-feldspar and albite are called alkali feldspar .They are relatively hard at 6 on Mohs' hardness scale . Uses 20090925 http://uzmuh.en.ec21.com/Potash_Feldspar--2180803_2180833.htmlDetailed Product Description K-feldspar ore from Turkey Sio2: 75% Al2o3: 13% K2o: 5.4% Na2o: 2% Fe203: 1% max Tio2: 0.020071127