Mabel | Mid-Century Atomic Opal Ring in 10k Gold, c.1950sMeet Mabel, A Late 1950s Natural Opal Cluster Ring This stunning example of 1940s to 1950s "Atomic" jewelry is a staple of the Mid Century Modern era: clusters of colorful white crystal opals are set surrounding a nucleus stone in a tall, floating fashion. While the gold may be stamped 18 karat, the piece tests to be about 10 karat gold; to the surprise of many collectors, this is not uncommon for the rings of this style and time. All of the opals