Different Formats for Different Numeric Values (Format Function) A user-defined format expression for numbers can have from one to four sections separated by semicolons. If the format argument contains one of the named numeric formats, only one section is allowed.
Hardness is a mineral's ability to resist being scratched. Minerals that are not easily scratched are hard. You test the hardness of a mineral by scratching its surface with a mineral of a known hardness. Mineralogists use Mohs Scale, shown in Table 3.2, as a reference for mineral hardness.
If a reference mineral both scratches and can be scratched by a certain test specimen, then the specimen is assumed to possess a hardness equal to that of the reference mineral in question. The set of reference minerals of the Mohs' scale can be supplemented by a few common household items.