Mohs scale of mineral hardness - WikipediaThe Mohs scale of mineral hardness is a qualitative ordinal scale characterizing scratch . 4, Fluorite, CaF2, 21, Fluorite with Iron Pyrite.jpg. 5, Apatite.mohs scale hardness iron ore,Mohs Scale of HardnessIn 1812 the Mohs scale of mineral hardness was devised by the German . 4-5, Iron. 5.5, Knife blade. 6-7, Glass. 6.5, Iron pyrite. 7+, Hardened steel file.
mohs scale hardness iron ore