c. Mohs' Hardness scale is based on relative hardness of minerals from softest=1 (talc) to hardest=10 (diamond).
(Mohs' Hardness scale; is based; on relative hardness of minerals from softest=1 (talc) to hardest=10)
Mohs' Hardness scale
is based
on relative hardness of minerals from softest=1 (talc) to hardest=10