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 have since patched things up and have even performed on stage together. Industrial metal suffered a critical backlash at the turn of the millennium. In an April 2000 review for the "Chicago Sun Times", Jim DeRogatis dismissed Nine Inch Nails' new music as a "generic brand of industrial thrash" and accused Ministry of repeating an act that "was old by 1992". Although "The Fragile" reached the top spot of the "Billboard" 200 and went on to earn double platinum status, DeRogatis considered it a "flop" nonetheless. Around this time, veteran industrial metal artists (Ministry, Godflesh, and White Zombie) began to