Australian Insect Brooch

An Australian insect brooch with Tasmanian Trigonia shell wings and an opal and green stone doublet on 9k gold. Circa 1900-1920. Trigonia has a triangular shell with distinctive concentric ridges on its surface as well as nodular outgrowths.
Condition: Very Good with minimal wear consistent with age and use.
Dimensions: Weight 1gm, Length 4cm, Width 2cm, Height 0.5cm