[1.8] Help with blocks

I want to create a new block, let's say an amethyst block.

This line is what I already have (in the init):

Minecraft.getMinecraft().getRenderItem().getItemModelMesher().register(Item.getItemFromBlock(block_amethyst), 0, new ModelResourceLocation("mymodid:block_amethyst", "inventory"));

Is that correct?

Ok, if yes, which files do I need to create? And in which package(s)?