Make the Grimstone only minable with diamond pickaxe

Make that only diamond pickaxe can mine Grimstone as for the wooden pickaxe for the normale stone in that way it would form a sense of progression for mining, if you want to get in a layer where diamonds a common you first need to find 3 diamonds in the stone layer where they are rare, you could also add dungeons on the grimstone layer with resources only for the one who mined diamonds like the end city, for you to get there you first need to do something else