Job 41:24
His heart is as firm as a stone; yea, as hard as a piece of the nether millstone.
Ezekiel 11:19
And I will give them one heart, and I will put a new spirit within you; and I will take the stony heart out of their flesh, and will give them an heart of flesh:
Ezekiel 36:26
A new heart also will I give you, and a new spirit will I put within you: and I will take away the stony heart out of your flesh, and I will give you an heart of flesh.