Iron: The Original Black MetalBriefs by joanismylover, the third metal attorney.
Iron “is the most common element (by mass) forming the planet Earth as a whole, forming much of Earth's outer and inner core. . . Iron metal has been used since ancient times.” Add the right amount of carbon, and iron “produces steel, which may be up to 1000 times harder than pure iron.” These “[s]teels and low carbon iron alloys … are by far the most common metals in industrial use, due to their great range of desirable properties and the abundance of iron.”*
So too is “Iron” the most common word in my iTunes metal library, a search of which results in six different artists, 39 different albums, and a whopping 420 songs. Certainly, iron has been employed “since ancient [metal] times” being wielded to all time heavy metal thunder perfection by Iommi and co way back in 1970 – “Iron Man” practically started it all.
And now, thanks to the FULL METAL ATTORNEY, I have three more Iron Bands: Iron Curtain, Iron Dogs, and Iron Kobra. Certainly these bands recognized that Iron is “by far the most common [of the] metals in  use, due to their great range of desirable properties.” And we get some great, some desireable, and some that need work in this range of Iron metal products.
*From: http://en.wikipedia.org/wiki/Iron, accessed January 9, 2013.