'Iron' in the Bible

(And the stones used in the building of the house were squared at the place where they were cut out; there was no sound of hammer or axe or any iron instrument while they were building the house.)

For they are your people and your heritage, which you took out of Egypt, out of the iron fireplace;

And Zedekiah, the son of Chenaanah, made himself horns of iron and said, The Lord says, Pushing back the Aramaeans with these, you will put an end to them completely.