MnO2 - Manganese dioxide

Battery grade high-purity manganese sulfate

PG17 - Chromium green-black hematite

PBk33 - Iron manganese black oxide

PBk30 - Chrome iron nickel black spinel

PBk28 - Copper chromite black spinel

PBk27 - Iron cobalt chromite black spinel

PBk26 - Manganese ferrite black spinel