Life Crystal

A Life Crystal is an item that drops when a Crystal Heart is broken with a Pickaxe or Drill. When used, it permanently increases the player's health capacity by 20, adding a red heart to the player's health bar, while also restoring 20 health. Life Crystals are consumed upon use. It can be found in the Underground and Cavern layers. It also has a 1/10 chance to drop from a pre-hardmode Golden Crate, and 1/15 from a hardmode Titanium Crate.

Up to 15 Life Crystals can be used, increasing health capacity by 300 (15 hearts). Added to the 100 health new players begin with (5 hearts), a total of 400 health (20 hearts) can be achieved. Additional Life Crystals can no longer be used at that point, and attempting to do so will not consume the item. Extra Life Crystals acquired thereafter can be sold for coins, or used to craft Heart Lanterns.

After a world converts to Hardmode, and after the 400 health maximum is reached from consuming Life Crystals, Life Fruits can then be used to increase health capacity further, to a maximum of 500 (20 Life Fruits).

Trivia

 * Life Crystals can be considered the health counterpart to Mana Crystals.
 * As of the 1.4.0.1 update on desktop, Life Crystals have a 1 in 10 chance (10% chance) to be found in Golden Crates when fishing.

History
Lebenskristall Cristal de santé 生命水晶