Hardness measures a gemstone's resistance to scratching, which is related to the ionic or atomic bonding strengths of the minerals and their chemical components. The most widely used measuring standard for mineral hardness is the Mohs Scale of mineral hardness, created by Austrian mineralogist Friedrich Mohs in 1822, which ranks and standardizes the scratch resistance based on 10 minerals: diamond, 10; corundum, 9; topaz, 8; quartz, 7; orthoclase feldspar, 6; apatite, 5; fluorite, 4; calcite, 3; gypsum, 2; talc, 1. The larger the number, the greater the hardness. The scale is relative between each mineral; there is no absolute ratio between each hardness level.