which mineral scratches dolomite and is scratched by olivine?
Apatite: Hardness 5 Dolomite has a hardness of 3.5 to 4, while olivine has a hardness of 6.5. Apatite, or any other mineral with a hardness of 5 is what you are looking for
Of the minerals on Moh's scale of hardness, the ones that fit your requirement would be Fluorite H-4, Fluorapatite (formerly called apatite) H-5, and Orthoclase (Feldspar) H-6.
