One of a kind opal pendant set with a 14kt yellow gold cap and bale. The opal is a rare opalized seashell from Australia. The lapidary work is by Bruce London from Harwich on Cape Cod.  The metal work is by S&R Goldsmiths in Olreans, also on Cape Cod. Opal is approximately 1 1/8" high. Chain is not included.
 
Australia's opal mining areas were once an inland sea. Many fossils are found in these ancient beds, including opalized sea shells. A shell gets buried in the sand. The organic matter decays, leaving a shell-shaped void in the sand. The void fills with sand-bearing water that solidifies over time to become precious opal. These full color shells and shell fragments are exceptionally rare.