Hardness Item 1 Talc 2 Gypsum 3 Calcite 4 Fluorite 5 Apatite 6 Orthoclase Feldspar 6 Titanium 7 Quartz 8 Topaz 9 Corundum 10 Diamond 2.5 to 3 gold, silver, aluminum 2.5 fingernail 4 platinum 4 to 5 iron 5.5 knife 6 to 7 glass 6.5 iron pyrite 7 to 8 hardened steel...
Mohs Scale - Typical Materials Mohs HardnessTypical Material 1 Talc 2 Gypsum, Rock salt 2.5 Fingernail, pure gold, silver, aluminum 3 Calcspar (calcite), copper coin (penny) 4 Fluorspar (fluorite) 4.5 Platinum, iron 5 Apatite 6 Felspar, orthoclase, titanium, spectrolite 6.5 Steelfile, iron ...
The Mohs Hardness Scale is a standard that indicates the hardness of minerals. It was first proposed by German mineralogist Frederich Mohs in 1822.
This is evidence of the hardness of sapphire and a testament to its place at number 9 on the Mohs hardness scale. More germane to this discussion of gemstone hardness though, is the reason why sapphire and ruby (of the same family, Corundum) are so highly recommended for everyday wear je...
Talc and pyrophyllite cannot make mixed crystals because of large differences in ionic radii of magnesium and aluminum. Talc [Mg3 (OH)2 Si4O10] crystallizes in monoclinic and triclinic system. It most often occurs as foliated to fibrous masses. Talc has low hardness of 1 in Mohs scale and ...