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
Industrial metal collaborations with and remixes from industrial metal musicians. When industrial metal climbed the charts of the late 1990s, its sudden popularity was met with negative reactions from the early innovators of industrial music. Peter Christopherson told "The Wire" that he no longer felt any kinship with the industrial scene: "this is not me, this is not what I'm about". Lustmord, a prominent early industrial musician, declared that "Ministry just doesn't interest [him]" and "[he has] no time for all this rock and roll shit they're doing now." Skinny Puppy frontman Nivek Ogre dismissed Nine Inch Nails as "cock rock" but