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 Complete", Obituary's most successful album. The other band members' refusal led him to form Meathook Seed. In the early years of the 21st century, groups from the black metal scene began to incorporate elements of industrial music. Mysticum, formed in 1991, was the first of these groups. DHG (Dødheimsgard), Thorns from Norway and Blut Aus Nord, N.K.V.D. and Blacklodge from France, have been acclaimed for their incorporation of industrial elements. Other industrial black metal musicians include Samael, The Axis of Perdition, Aborym, and ...And Oceans. In addition, The Kovenant, Mortiis and Ulver emerged from the Norwegian black metal scene, but