Wool

Wool is a block derived from sheep that can be dyed in any of the 16 different colours. Wool blocks are weak, very flammable, and offer little resistance against explosions. Wool is harvested by right-clicking a sheep with Shears (2 - 4 wool) or killing it (1 wool). White, light gray, gray, black, brown, and pink wool can be found naturally by harvesting it from the respective sheep. Before the 1.7 update, wool could be obtained by hitting sheep without a tool.

Uses
Wool is a key component of Beds and Paintings and suitable for docks, as wool blocks will stop boats and absorb some impact from collisions in a manner similar to Soul Sand.

Painting sheep (right-clicking while holding dye) is a highly recommended method of obtaining coloured wool, as the sheep will drop 2 - 4 blocks of wool when shorn - a significantly larger yield vs. crafting wool with dye or killing a dyed sheep. Non-white sheep (brown, pink, black, grey, and light grey) can be dyed just as easily as white sheep, with no need to 'bleach' them back to white using Bone Meal before re-colouring them with another dye.

Wild Wolves can be located by looking for randomly dropped blocks of wool on the ground (especially in Forest or Taiga biomes) as wolves will kill sheep while roaming.

Occurrence
Aside the sheep, black wool blocks can also be found naturally in NPC Villages where they lie on top of a fence post, surrounded by 4 torches.

Crafting
Wool can be crafted from string if required. However, as sheep are much easier to collect from than spiders are to kill, doing so may be a waste of resources. But with the Adventure update, string can be collected very easily for bows and beds (and perhaps even fishing rods, if low on food) for use underground.

As a Crafting Ingredient
Note: Any colour of wool may be used, but it has no effect on the product's final appearance.

Coloured Wool
The placement of the wool block and dye doesn't matter as long as they are both in the crafting grid.

Data Values for Colored Wool
Different colours of wool can also be obtained by adjusting the "damage" values in the inventory. * = Turns to white wool when placed.

History
Wool was added for the creation of carpeting, colourful structures, and in-game pixel art. Before leather was available, wool was also used to craft leather armour.

In Creative Classic mode, wool blocks were known as cloth blocks that came in a set of 16 colours, although the palette was slightly different from the one available in Beta. Three shades of gray were added in Classic 0.0.20a.

Coloured wool blocks were unobtainable during Classic's Survival Test and Indev unless they were pre-placed into the map file. Coloured wool blocks were completely removed from the code in Infdev. Placing these blocks on the map would cause the game client to crash, since the blocks no longer existed.

Wool could first be used to craft Paintings in Indev.

In Beta 1.2, cloth blocks were renamed wool blocks and could be 16 different colours. White sheep could be painted by right-clicking on them while holding any dye. Light gray, gray, and black sheep could now appear alongside white ones in the environment.

As of Beta 1.4, brown and pink were added to the naturally occurring palette of coloured sheep.

After Beta 1.6.6, the crafting recipe for a block of wool was changed, reducing the amount of string required from 9 to 4 units.

Trivia

 * Sheep have a 5% chance to be black, 5% chance to be gray, 5% chance to be light gray, 3% chance to be brown, and a 0.174% chance to be pink. The remaining 81.826% are white.
 * Without sufficient lighting, hostile mobs can spawn on placed wool blocks.
 * As of the 1.7 update, wool will release particles of its respective colour when being mined. In previous versions, no matter what colour the wool was, the particles released while being mined would be white.
 * The damage values for the wool and the dyes are the inverse of each other.
 * The only way to get the purple error block is to use an inventory hack. It does not have the same texture as a normal wool block when held, but if placed will turn into normal white wool. This was probably meant to be a seventeenth color that Notch never put in, as the texture it uses is right next to the other wool block textures.
 * As of 1.9, the purple error block now looks like the first stage of growing Nether Wart. This is due to the pink block that it used being replaced with the texture for it.
 * Shears do not take damage from destroying wool blocks.
 * There is a bug that in multiplayer, when a wool block is placed in water next to sand in front of a grass block, the grass block will turn into sand.

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