I have seen these 1920s black amethyst glass pedestals, stands, or risers in many of glass identification books displaying Art Deco and Depression era glass bowls and vases. I remember seeing an old advertisement for one like it in one of my books. The riser's display area center ring is 4 inches diameter. It's 1-3/4 inches high by 7 inches wide across the 3-footed base. The underside has a raised in-mold mark reading 616 NAP. In excellent condition with no damage.