Jelaskan Rujukan dari Skala Mohs dalam bahasa melayu

Mohs hardness of elements is taken from G.V. Samsonov (Ed.) in Handbook of the physicochemical properties of the elements, IFI-Plenum, New York, USA, 1968.

Cordua, William S. "The Hardness of Minerals and Rocks". Lapidary Digest, c. 1990.