Clock

"Keep track of the scary time! A craftable watch lets you know when it's safe to emerge from the caves."

- The Halloween Update promo poster

Clocks are items that display the current in-game time by displaying the sun and the moon's position relative to the horizon.

Trading
Expert-level librarian villagers have $1/3$ chance to sell a single clock for 4 emeralds as part of their trades.

Expert-level librarian villagers have a 50% chance to sell a clock for 5 emeralds.

Usage
The clock dial consists of two halves, a day side and a night side. The dial spins clockwise slowly to indicate the time of day, corresponding to the sun or moon's actual position in the sky. The player is able to sleep a few seconds after the clock shows exactly dusk.

The dial can be read from a clock in any of its representations: held in a player's hand, placed in any inventory or crafting grid, in an item frame, and even as a dropped item.

Because there is no day/night cycle in the Nether or the End, clocks do not work properly in these dimensions. Instead, the dial rotates rapidly and randomly, making them useless.

Video
Note: This video doesn't state that Clocks can be found in buried treasure.

Trivia

 * $1/3$, a clock can be viewed under the item statistics page as long as one obtained a clock at some point. It can also be viewed in recipe book if the recipe for it has been unlocked.
 * $$, the default resource pack for the clock contains 64 individual frames, each frame lasting about 18.75 seconds in real time (375 ticks) (1350 seconds (22 minutes, 30 seconds) in minecraft time).
 * When the time of day changes suddenly, such as after sleeping or when is used, the clock dial will spin rapidly to catch up.
 * After completing 100 day-and-night cycles $$, the player is awarded an achievement.
 * Although clocks do not function in the Nether or the End, the actual day-night cycle does continue.
 * Despite that redstone is used in its crafting recipe, this item is neither a redstone component nor a redstone power source.

Hodiny Uhr Reloj Montre Orologio Óra 時計 시계 Klok Zegar Relógio Часы 时钟