Diamond is a block in the game CastleMiner. It is a block found in the ground. You can not currently place the block. Axe skeletons also drop it. Diamonds in Castleminer Z are blue gems in your Avatar's hand after you mine them. They can be crafted into Diamond bullets, walls, tools, and even guns, but they are very rare in short distances and are often found in the most dangerous of places in the game, like caverns, along with Bloodstone.