The mineral is structured solid found in nature, with a fixed chemical composition. If a mineral scratches glass, the property hardness of the mineral is measured. The property hardness refers to the mineral's resistance to being scratched. In odrer to determine this property, scientists use the Moh's Hardness Scale. According this scale the mineral can be categorized as: talc, gypsum, calcite, fluorite, apatite, orthoclase (feldspar), quartz, topaz, corundum or diamond.