Minecraft wiki entry for Metadata_variants, associated text: It is extremely likely that these were the result of the bell being incompletely programmed. The bell can face four directions, and at this point there were four different types of bell (the stone bell alongside these three), which would correspond to the four orthogonal facing directions. Since at this point granite and diorite were stored as data value of stone, it seems reasonable to expect that these would result from drawing from that data value of the used stone texture. Attempting to place a bell with data value 4 or above would fail; there were as a result no polished diorite, andesite or polished andesite bells, as these would not have any facing directions to correspond to. As they later spawned in villages, this would also imply that these were intended to be directional bells.