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 Hard Rock Video), and Marilyn Manson's output with Richard Kern and Floria Sigismondi. NIN later collaborated with Bill Viola for live accompaniment. Trent Reznor also produced the soundtracks for the films "Natural Born Killers" and "Lost Highway", and served as "musical consultant" for "Man on Fire". Rob Zombie has directed three films. As of 2009, Marilyn Manson is in the process of directing "". Other films that have included prominent contributions from industrial metal artists include "The Crow", "Johnny Mnemonic", "Spawn", "The Matrix", "Blair Witch" and "A.I. Artificial Intelligence". Its emphasis on transgressive themes has made a few industrial metal