Fossilized Clams with Opal Replacement
Australian opal replacement of clam fossils. As the natural organic material deteriorates over time, opal deposits fill in the shape of the creature making it a fossil, and a mineral together! A rare and unique find!
Measurements: ~3" long x 1-¾" wide x 1-¼" deep
Location: South Australia, Coober Pedy Opal Fields
Time Period: Cretaceous ~135 MYO
Opal is composed of hydrated silica. It is an amorphous silicate, meaning it does not form crystals. Opals are structurally composed of tiny spheres of silica, which when arranged in perfect geometry create the famous play of color associated with the stones. The arrangement of silica balls acts like a prism, which allows the rainbow spectrum of colors to be visible to the naked eye. Opal has been a stone of myth and mysticism for thousands of years. It was once worn for protection against sorcery and to enhance a person’s magical qualities. The idea that Opals are unlucky came about in 1829 after the publication of Scottish novelist Sir Walter Scott’s book Anne of Geierstein. In the novel, an Opal amulet signifies the downfall of the heroine, and this act of literature negatively affected the entire Opal industry for generations.