This is a 1" shallow, rectangular frame fronted with a glass panel (or no glass) and it is used to show and at the same time protect items on display, as paintings, coins, or jewelry. The big stones formed a sort of shadow box, causing the markings to appear in bold relief. The objects presented in a shadow box can be a  grouping with artistic or personal significance. The grouping of the objects and the depth effect created by their relative heights from the backing creates a dramatic visual result.