5.12 Ct wood replacement opal Tucson A beautiful extra small green-blue

A beautiful extra small green-blue boulder opal

the wood structure remains visible within the opal

A great bright green-blue boulder opal

Opal ID 3500 is a dreamy pastel boulder opal

A beautiful green and blue free-form boulder opal

5.12 Ct wood replacement opal Tucson A beautiful extra small green-blueA rare and unusual dark purple wood replacement opal. What is Wood Replacement opal? Opal formation commences when silica dissolves in water. At our Russells opal mine we have found that this silica solution occupies a void most probably left by decaying tree roots or branches. In cases where the silica infiltrates organic material before complete decomposition occurs, the organic molecules are replaced by silica. This remarkable process results in