Clock

A Clock displays the positions of the sun and moon. It was added in Update 0.8.0.

Usage
Clocks can be used to measure time in Minecraft PE. They can also be used while mining as to alert the player whether it is safe to come out of the cave or not. The clock's movement if from left to right, same as of a real clock. The blue background color means its day while the black background color means its night.

Crafting
1 Redstone + 4 Gold Ingots = 1 Clock

Trivia

 * Clocks were added in 0.8.0, when Redstone Ore became mineable.
 * Clocks are similar to a compass but compasses tell direction rather than time.
 * Clocks were useless in the Creative inventory until 0.10.0 when day/night cycles were added Creative.
 * Clocks have a similar crafting recipe to a Compass.
 * The difference is that the Iron Ingots are replaced by Gold Ingots.
 * After waking up from a bed, the clock is exactly half-blue and black.
 * And you can only sleep if the clock is half-back and blue.