What are wood replacement and crystal opals?

Opal Fossils with Preserved Internal Details

Opal formation commences when silica dissolves in water. At our Russell's 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 meticulous preservation of intricate internal structures. Consequently, the wood structure remains visible within the opal.

Our “wood replacement” opal is truly exquisite, not only because it is an opalised fossil, but because the remaining internal structures create a mesmerizing inner world that is visible through the transparent and translucent opal.

 

Opal Fossils with Unpreserved Internal Details

Opal formation commences when silica dissolves in water. At our Russell's opal mine we have found that this silica solution occupies a void most probably left by decaying tree roots or branches. When it solidifies it creates an opalized replica of the original object. These are also known as 'jelly mould' fossils.

In some rare cases we have found large and rare opal fossil specimens with beautifully preserved external features and pure crystal opal ‘branches' or 'roots’ within.

The smaller and more fragmented pieces yield thick "crystal opal" that we carve into transparent and translucent opal gemstones.