Minecraft wiki entry for Barrier, associated text: Barrier blocks are mainly used to build an impenetrable barrier that cannot be broken in standard survival mode play but can be placed in survival. For example, they can be used to protect a reserved area from entry by players, mobs, and other entities. Unlike other kinds of unbreakable blocks that could be used for this purpose (such as bedrock), barrier blocks are unobtrusive because they are invisible. Barrier blocks cannot be destroyed by TNT, Creeper explosions, or any other explosions.