8.24 Ct 3D wood replacement opal Colour_Green A lovely purple and grey

A lovely purple and grey boulder opal heart

51 Ct wood replacement heart opal

61 Ct wood replacement opal

49 Ct wood replacement opal in a teardrop shape

A small bright rainbow boulder opal

8.24 Ct 3D wood replacement opal Colour_Green A lovely purple and greyA lovely 8. 24 Ct wood replacement opal in a large teardrop 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 process