Job 41:24
His heart is as hard as stone, and as fast as the stythie that the hammer man smiteth upon.
Isaiah 48:4
Howbeit, I knew that thou art obstinate, and that thy neck hath an iron vein, and thy brow is of brass.
Jeremiah 5:3
Where as thou, O LORD, lookest only upon faith and truth. Thou hast scourged them, but they took no repentance: thou hast corrected them for amendment, but they refused thy correction. They made their faces harder than stone, and would not amend.
Zechariah 7:12
Yea, they made their hearts as an Adamant stone lest they should hear the law and words, which the LORD of Hosts sent in his holy spirit by the prophets afore time. Wherefore the LORD of Hosts was very wroth at them.