Speculum metal metal mixtures usually contain two parts copper to one part tin along with a small amount of arsenic, although there are other mixtures containing silver, lead, or zinc. The knowledge of making very hard white high luster metal out of bronze-type high-tin alloys may date back more than 2000 years in China although it could also be an invention of western civilizations. Such metals were used in sculpture and to make more effective mirrors than the more common yellow easily tarnishing bronze mirrors. In that era mirrors of speculum metal, or any precious metal, were rare and only owned by
Nth metal mineral causes whatever is irradiated with it to float and defy gravity, like in the comics. The Nth Element is used in Hawkman's equipment, and Black Mask attempts to use it for a bank heist. In "", Batman uses Nth metal brass knuckles, handcuffs, as well as batarangs, to fight and capture Gentleman Ghost. Green Arrow is shown to have Nth metal tipped arrows. As shown in the animated "Justice League", Nth metal can be used against supernatural beings, but is vulnerable to direct magical spells, as is seen when Equinox mystically melts Batman's Nth metal handcuffs. In "The Flash"