Fanon:Fire Crystal

is a rare ore that is obtained from Fire Crystal Mines, you need 4 of them to get a maxed out. When you get fire crystals, you need 40 of them to create a MAX level Ray Gun.

Technical
Those ores are rare and are very important to upgrade Wonder Weapons, it's recommended to have Gold Weapons to get these, they'll be saved but only the half of them.

Strategies
When you die, your fire crystals will be saved, but only a half of them are saved upon death. You need to find them to MAX your Ray Gun.