Definition of: Mohs scale

(mōz) Mineral.
A qualitative scale in which the hardness of a mineral is determined by its ability to scratch, or be scratched by, any one of 10 standard minerals arranged in the following increasing order of hardness: 1, talc; 2, gypsum; 3, calcite; 4, fluorite; 5, apatite; 6, feldspar; 7, quartz; 8, topaz; 9, corundum; 10, diamond. [after Friedrich Mohs, 1773–1839, German mineralogist who conceived it]