Life Crystal

Life Crystal is a healing item that increases the player's maximum life by 20, adding another heart to the player's life bar. It also restores 20 life when used, only slightly more than a Mushroom.

Life Crystals are obtained by smashing a Crystal Heart with a Pickaxe. Crystal Hearts are found in any underground biome, but are especially prevalent in the Dungeon and The Underworld. A player can use a total of 15 Life Crystals, increasing their life to 400. After this, trying to use a Crystal will result in the animation, but will have no effect and will not consume the Crystal. Therefore, they cannot be used to reach the health maximum of 500, and the player must instead collect Life Fruit from the Underground Jungle. Despite this, it is recommended to keep collecting Life Crystals, as they have a high sell value and can be used to craft Heart Lanterns.

Crafting
The life crystal isn't crafted. It is found underground, and is a common item.

Bugs
In mobile, if clicked on but immediately switched out, your health will increase, but the Life Crystal will still be there, and one of the item you switched to is taken away.

Trivia

 * In the alpha version, bosses dropped Life Crystals.
 * Prior to the 1.2 update, this item was the only means of increasing a player's maximum health. Life Fruits were added in 1.2 to further increase a player's health.