Helmets are headwear that provide the strongest protection against damage when equipped. However, they don't help reduce cold, like the Chapkas - this means players have to sacrifice one advantage for another by wearing headwear. Helmets are generally used for combat. There are currently three tiers of helmets, with the fourth (amethyst helmet) being added in the next update.
The stone helmet is the lowest tier of helmets, and provides the lowest protection. They are useful, however, at times, especially in the earlier stages.
The golden helmet is the middle tier of helmets, and provides considerable protection.
The diamond helmet is currently the high tier of helmets, and provides strong protection.
The amethyst helmet is currently the highest tier of helmets, and provides maximum protection.