And they set in it four rows of stones - See all these precious stones particularly explained in the notes on Exodus 28:17 (note), etc.

a diamond. The word yahalom may mean the diamond, from halam, to beat, smite, because of its extreme hardness, by which it will beat to pieces the other stones. It is a fine pellucid substance never debased with any admixture of other matter; susceptible of elegant tinges from metal-line particles; giving fire with steel; not fermenting with acid menstrua; scarcely calcinable?? by any degree of fire; and of one simple and permanent appearance in all lights. It is the hardest and most valuable of all gems; when pure, perfectly clear and pellucid as the clearest water, and eminently distinguished from all other substances by its vivid splendour, and the brightness of its reflections.