Sun Spit(3.5e Equipment)
From D&D Wiki
This metal is found on the inside of active volcanoes. It's collected while it's in a gel-like phase and then then laid out in running water to cool and harden the metal before it's forged.
This metal can only be gathered from volcanoes that have gone off in the past 3 days, otherwise the metal becomes super hardened and can't be used to craft with. The metal takes 4 days to cool and if removed any sooner than that the metal is treated as standard steel. Any weapon crafted with this metal deals an extra die of damage and it's considered to be flaming even though there is no fire on it. Any armor crafted with this metal has its AC bonus increased by 2 and Max Dex bonus brought down by 1.
Masterwork Side rule: When used to craft masterwork armor if the check beats the DC by 15 points or more then the armor has a DR 10(Fire)/15(Cold). If used to make a weapon, then when a critical is confirmed the weapon deals an addition 2 die of fire damage.
Sun Spit has 30 hit points per inch of thickness and hardness 20.