Emery

Emery is a stone introduced by Engineer's Toolbox, the primary use of which is in crafting the Grinder block. It comes from Emery ore, which can be mined with a stone pickaxe and drops one Emery and some XP. It looks like Emerald ore, except with the green replaced by black. It often spawns in Extreme Hills biomes.

Texture
It is similar to the Diamond's texture, except that it's black.