The Diamond Protection was the first heat protection to be implemented into the game. It helps to reduce the heat gain in the Lava Biome. However, its heat protection is weak, and you still need to take a lot of ice cubes with you to survive.
All weapons will only deal 20% damage to the lava monster, except for the reidite sword and lava sword. This makes all weapons that aren't either of those almost useless.
The diamond protection was added in the "It Smells Like Burning!" update.
It gives you little player defense and little mob defense.
Used to craft Amethyst Protection.