Deuteronomy 24:6
No man shall take the nether or the upper millstone to pledge: for he takes a man's life to pledge.
Nave's Topical Index—AKJV

Job 41:24
His heart is as firm as a stone; yes, as hard as a piece of the nether millstone.
Nave's Topical Index—AKJV

Isaiah 47:2
Take the millstones, and grind meal: uncover your locks, make bore the leg, uncover the thigh, pass over the rivers.
Nave's Topical Index—AKJV