"The old man wore a breastplate"
by cm

Breastplate of the Jewish Kohen ha-Gadol
Public DomainBreastplate of the Jewish Kohen ha-Gadol - Credit: 1905-1906 Jewish Encyclopedia
Breastplates were traditionally worn by High Priests in Judaism, with twelve precious stones to represent the twelve tribes of Israel.  Urim and Thummin were contained in a fold.  The prototype is described in Exodus:

And thou shalt make the breastplate of judgment with cunning work; after the work of the ephod thou shalt make it; of gold, of blue, and of purple, and of scarlet, and of fine twined linen, shalt thou make it... Exodus 28:15-30