Mohs Hardness Scale Hardness Mineral Other 10 Diamond 9 Corundum 8 Topaz 7 Quartz 6 Orthoclase 5.5 glass 5 Apatite steel nail 4 Fluorite 3.2 copper penny 3 Calcite 2.2 fingernail 2 Gypsum Talc Luster The shine of the mineral.