Brass than in brass produced by cementation. These may be "natural alloys" manufactured by smelting zinc rich copper ores in redox conditions. Many have similar tin contents to contemporary bronze artefacts and it is possible that some copper-zinc alloys were accidental and perhaps not even distinguished from copper. However the large number of copper-zinc alloys now known suggests that at least some were deliberately manufactured and many have zinc contents of more than 12% wt which would have resulted in a distinctive golden color. By the 8th–7th century BC Assyrian cuneiform tablets mention the exploitation of the "copper of the mountains"
Industrial metal repudiate the industrial label. Sales remained high throughout 2000–2005; at least 10 million records were sold during that time frame. Many groups began to take influence from hip hop and electronic music, in addition to industrial metal. As a result, acts like Powerman 5000 are often described as industrial metal as well as nu metal. Several industrial metal groups have produced eye-catching videos. These include Godflesh's collaboration with Andres Serrano, Aidan Hughes's graphics for KMFDM, Nine Inch Nails' work with Mark Romanek, Rob Zombie's visual work for White Zombie (for which he received the MTV Video Music Award for Best