Verses with the word millstone in the Old Testament (4 verses):

Deuteronomy 24:6
No man shall take the nether or the upper millstone to pledge: for he taketh a man's life to pledge.

Judges 9:53
And a certain woman cast a piece of a millstone upon Abimelech's head, and all to brake his skull.

2 Samuel 11:21
Who smote Abimelech the son of Jerubbesheth? did not a woman cast a piece of a millstone upon him from the wall, that he died in Thebez? why went ye nigh the wall? then say thou, Thy servant Uriah the Hittite is dead also.

Job 41:24
His heart is as firm as a stone; yea, as hard as a piece of the nether millstone.