Susan Niditch argues that Job 19:24 is a reference to using an iron stylus to write on lead.
Susan Niditch, Oral World and Written Word: Ancient Israelite Literature (Louisville, KY.: Westminster John Knox Press, 1996), 71
Stone can provide a surface for monumental inscriptions. Basing themselves on Jer. 17:1 and Job 19:24, some suggests that an “iron pen and stone stylus could have been used as chisels to carve into the stone” although “no artifact or pictorial evidence of these tools in ancient Israel has yet been found.” Job 19:24 is better translated “iron stylus and lead,” perhaps revealing something of another ancient Israelite writing technique.