Molded glass holiday or Christmas ornament, geometric shape, faceted sides, with some facets horizontally ribbed, and some sides with diamond design. Thin bent wire hook attached. Opening on top and bottom would allow a hook to travel through the ornament body, and have multiple ornaments hooked one on top of the other in a chain. This style of hook and ornament was designed and produced by the SHINY BRITE Company after WWII, and was discontinued in 1960. No mark.
Maker is possibly SHINY BRITE Company.