Once the player reaches a critical level of health aka half a heart, then the stone would kick in and restore the player to full health. Originally i thought that the stone should have only one use out of but if it was very rare this could be changed to 3/3 uses of the stone. After these uses the stone would be used up and the player would need to get a new one.
Problems with this:
Instant death by falling this could be an issue with how the server reads client health?
Drowning holding you under the water?
Poison taking you to the edge and not killing you?
Hits that do a lot of damage in one go boss/explosions?
Here is the artwork for it:

Hope you like my idea tell me what you think
