Night Crystal

The Night Crystal is a Accessory that gives extra  and  during the night. It is unlocked at. Its opposite is the Day Crystal, and it takes the shape of a Nether Star.

In total, it takes 26,240 Quartz to craft, which is equivalent to 410 stacks, which costs around from the Bazaar.

Crafting
Quartz can be found in the Blazing Fortress but it is recommended to use a Quartz Minion, because a lot of new players are farming Quartz for Mining EXP or EXP. In general, mining manually is really inefficient.

Trivia

 * The Night Crystal and the Day Crystal were once used in making a (technically) blacklisted accessory called the Eternal Crystal.