The artist of these adorable earring used opalite or lab created opals and set them in a beautiful sterling leaf design. The use of opalite came on strong in the early 1990's and because of its popularity has only increased over the years. Lab created opal have beautiful color and take very little care as compared to natural opals.
The earrings are signed on the back with RB inside a bear 925 which is the hallmark of Running Bear Trading Co. out of Gallop NM. There have always been shops in the southwest who will employ Native American to make jewelry. In Colorado Springs back in the 70's there was a large on called Broken Arrow and they produced a lot of fine jewelry. I am not familiar with Running Bear but I am sure it is the same type of operation. Specifics:
Metal: Sterling stamped 925
Signed: RB for Running Bear Trading Post
Size of Earring: 7/8" not including ear wire 1 1/4" with ear wire
Weight: 3.4 grams