2.13 Ct heart wood replacement opal Colour_Green A lovely lighter green and

A lovely lighter green and purple boulder opal

86 Ct wood replacement opal in a classic rectangle shape

110 x 50 mm

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

A beautiful black boulder opal with bright greens and blues

2.13 Ct heart wood replacement opal Colour_Green A lovely lighter green andA 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