Over 100 million years ago, giant clams known as Inoceramus lived in what is now the Australian outback. Some of these ancient bivalves had shells reaching up to 6.5 feet wide, making them among the largest of their kind and capable of producing large pearls.
Recently, experts confirmed that a fossil found in Queensland is the largest fossil pearl ever identified in Australia. The find was announced by University of Queensland professor Gregory Webb on August 26. The pearl measures just over three-quarters of an inch in diameter and was discovered in 2019 by a traveling fossicker at Kronosaurus Korner, a fossil quarry and museum located in Richmond, Queensland.
Millions of years ago, central Queensland was submerged under the Eromanga Sea, which supported many marine species including Kronosaurs—large marine reptiles described as “among the largest and most ferocious” by experts.
Michelle Johnston, curator at Kronosaurus Korner museum, recognized the rarity of the round stone found at the site and suspected it might be a pearl. She contacted Webb for further verification. Webb then worked with Dr. Joseph Bevitt from the Australian Nuclear Science and Technology Organisation to examine the specimen using a Dingo neutronCT scanner—a technique chosen to investigate its internal structure without causing damage.
“The results of that study have not yet been published, but it is safe to say that the sample is indeed a pearl, and the largest fossil pearl to be identified so far in Australia,” experts said.
Experts also noted: “Ancient clams dealt with small irritants by making pearls just as modern clams do. But for the ancient ones, we can see how they dealt with many other kinds of stress, including the kinds that finally killed them.”
The discovery highlights how much central Queensland’s environment has changed since prehistoric times—from an inland sea supporting diverse marine life to its current arid landscape.
