Blocks of coal can be used as fuel in a furnace. One block of coal lasts 800 seconds (16000 ticks), which smelts 80 items. This is ten times the duration of a single piece of coal and 11⁄9 times as efficient (+11.11%) as nine individual pieces of coal—which would only smelt 72 items. The latter, however, prevents inactive furnace use; while smelting one item with one coal wastes seven potential items, smelting one item with one block of coal wastes 79 potential items.
Note Blocks[]
Block of coal can be placed under note blocks to produce "bass drum" sounds.
Added blocks of coal to the April Fool's 'update', Minecraft 2.0, using a recolored version of the Block of Redstone texture. It could not be used as fuel and was only a compact block. When crafted back to coal, it would have an item data value of 32767 instead of 0, so it could not be stacked with other coal.
Coal blocks mentioned by Dinnerbone,[1] after their featuring in Minecraft 2.0. These would apparently be difficult to implement due to an analogous block made of charcoal requiring a separate block ID due to "logical issues".
Blocks of coal with numerical metadata variants 1 through 15, which are inaccessible through normal gameplay, now have no model rather than appearing identical to blocks of coal.
14w26a
Block metadata has been completely removed from this snapshot onwards with the introduction of block states. As this block never used block metadata at all prior to this version, fifteen unused, inaccessible metadata variants of it have been completely removed from the game:
A full stack of coal blocks should smelt for 14.2 hours – over 42 Minecraft days. That is over fifty times as many items as a lava bucket. However, the player needs 576 coal or 9 stacks of coal to do this.