Island Teardrop .. opalized wood
Gorgeous and dreamy opalized Indonesian petrified wood teardrop cabochon in a fine silver setting with dot wire accent and dew drop.  Double half round sterling silver wire ring shank 
size 8
This material is a type of petrified wood where the original wood has been replaced by opal. It's found in Indonesia, specifically in an ancient forest that was covered by volcanic flow millions of years ago. The Indonesian opalized wood is generally dated to the Miocene epoch, roughly 20 million years ago.