2.13 Ct heart wood replacement opal Colour_Green 86 Ct wood replacement opal

86 Ct wood replacement opal in a classic rectangle shape

A lovely boulder opal heart with a great stripy pattern

A beautiful 10

A very large and rare boulder opal from our Mt

A lovely large round boulder opal with a light body tone (background) and light pastel colours

2.13 Ct heart wood replacement opal Colour_Green 86 Ct wood replacement opalA lovely 2. 13 Ct wood replacement heart 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 the