Secret Rooms Mod 1.12 adds in many cool blocks that camouflage themselves to the surrounding world. That helps you hide your diamonds, or punish all who dare try to get to them without any notice. Hidden doors, pressure plates, hidden levers and more!
Anyways, pay special attention to the revolutionary Ghost block. This kind of block is totally visible but you can walk right through it. Covering a pit of lava by the floor made of these blocks, it become a dreadful trap for anyone who dares try stealing your diamonds.