E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
Luz or Luez.
The indestructible bone; the nucleus of the resurrection body.
How doth a man revive again in the world to come? asked Hadrian; and Joshua Ben Hananiah made answer. From luz in the backbone. He then went on to demonstrate this to him: He took the bone luz, and put it into water, but the water had no action on it; he put it in the fire, but the fire consumed it not; he placed it in a mill, but could not grind it; and laid it on an anvil, but the hammer crushed it not.Lightfoot.