Ferric Oxide : Min-94-98%Volatile Matters : Less than 1.0%Residue on 240 mesh (In Sieve) 63 Microns : Less than 1%Bulk Density (gm/cc) : 0.6MMoisture : Less than 0.5%Iron oxide is the most common colorant in ceramics and has the highest amount of iron. It is available commercially as a soft and very fine powder made by grinding ore material or heat processing ferrous/ferric sulte or ferric hydroxide.