Zamac (3.5e Equipment)
From D&D Wiki
Zamac is an alloy made basically of zinc. It has a great resistance to corrosion and rust. It looks like a slightly darker, shineless steel.
Due to it's low reactivity, whenever a mundane item made of zamac would be dissolved by acid of rust, it instead makes a reflex save with a bonus of +5 (as if it was a magic item). If even a magic item wouldn't be allowed a reflex save, then the zamac equipment will not be allowed either.
Any metallic equipment can be made of zamac, and it's cost is increased by 100 gp/kg (i.e. a full plate armor would cost 4000 gp: 1500 gp for the armor + 100 x 25kg)
Zamac has 10 hit points per inch of thickness and hardness 6.