6.96 Ct 3D Wood replacement opal Type_Pipe A lovely small rainbow and

A lovely small rainbow and caramel heart boulder opal

48 Ct wood replacement opal in a classic rectangle shape

98 Ct scarab carving from crystal opal

A beautiful 4

84 Ct larger teardrop boulder opal pair is perfect for creating elegant earrings

6.96 Ct 3D Wood replacement opal Type_Pipe A lovely small rainbow andA lovely 6. 96 Ct wood replacement opal in a soft half circle shape. 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