Iron
Genesis 4:22
And Zillah, she also bare Tubalcain, an instructer of every artificer in brass and iron: and the sister of Tubalcain was Naamah.
Numbers 31:22
Only the gold, and the silver, the brass, the iron, the tin, and the lead,
Deuteronomy 8:9
A land wherein thou shalt eat bread without scarceness, thou shalt not lack any thing in it; a land whose stones are iron, and out of whose hills thou mayest dig brass.
1 Chronicles 22:14
Now, behold, in my trouble I have prepared for the house of the LORD an hundred thousand talents of gold, and a thousand thousand talents of silver; and of brass and iron without weight; for it is in abundance: timber also and stone have I prepared; and thou mayest add thereto.