Opalized ammonite fossils are formed through a unique geological process involving the replacement of organic material with silica, which is the primary component of opal. This process can occur ...

The fossilization process itself can take anywhere from a matter of days to millions of years. Waiting for mineral-rich ...

A s bones encased in rock rotted away, water-borne silica seeped into the crevices, solidifying into opal and preserving precious details for 100 million years. The resulting fossils now provide ...

There are few fossils, but even they create controversy. The opal fields of Lightning Ridge in New South Wales have produced a few jaws and teeth of small monotremes. Steropodon and Kollikodon are ...