Beautiful and unique turquoise opal found inside petrified wood.

According to Geology.com, volcanic ashfall is the ideal environment for opal and petrified wood to form.
“One of the most common and best geologic environments for the formation of petrified wood is a forest buried by a volcanic ashfall. In this situation the ash buries the plants and protects them from decay and insect attack. The ash also serves as an abundant source of easily dissolved silica, which will be carried into the wood by moving groundwater where it precipitates in cavities and replaces the solid woody materials,” the website writes.

This pure form of opal is absolutely beautiful and is a popular and expensive mineral that is often used in jewelry and works of art.