This stone is opalized petrified wood in a bullet shape.  Accented with a small opal dot, a circle, and tube bail.  This comes on a 22" sterling silver figaro chain.  (Opalized Petrified Wood. Colorful crystal patterns are displayed in a cross-section of petrified wood in the Petrified Forest National Park, located in northeast Arizona. Wood opal is a form of petrified wood which has developed an opalescent sheen or, more rarely, where the wood has been completely replaced by opal.)

Opalized Petrified Wood