Fluorite, the primary mineral source of fluorine which gave the element its name,
was first described in 1529;
For example, if some material is scratched by apatite but not by Fluorite, its hardness on the Mohs scale is 4.5.
For example, if some material is scratched by apatite but not by Fluorite, its hardness on the Mohs scale would fall between 4
and 5.
For example,
if some material can be scratched by apatite but not by Fluorite, its hardness on the Mohs scale would fall between 4 and 5,
as the hardness of apatite on the Mohs scale is 5 and that of Fluorite is 4.