140 years ago, an agate specimen from India (a translucent mineral and semiprecious stone, a type of chalcedony quartz) was recorded in the Mineralogy Collection at the Natural History Museum (NHM) London. Now, a research team says that this agate was formed from a 60-million-year-old dinosaur egg.
The petrified (or “agatized”) egg probably belonged to a titanosaur during the Cretaceous period, common in what is now India.
Robin Hansen, the museum’s mineral curator, brought the specimen to the museum’s dinosaur experts Paul Barrett and Susannah Maidment. The group agreed that the agate was approximately the right shape and size to be a dinosaur egg, and determined that the outer texture of the mineral resembled that of an egg. Also, the outer edges of the specimen showed that other similarly shaped objects (such as an egg hatch) were found adjacent to the 6-inch-wide agate stone.
“This specimen is an excellent example of why museum collections are so important,” Hansen said in an NHM announcement. “In 1883 it was correctly identified and cataloged as an agate using the scientific information available at the time… , we realized that this specimen was something more special – agate filled this spherical structure and it turned out to be a dinosaur egg.”
Although titanosaurs were the largest land animals to have ever lived, they had eggs that were not very large. This was because the animals produced a brood of several dozen eggs per cycle, rather than a single larger brood.
According to the museum announcement, it seems likely that the agatized egg was formed due to volcanic activity in the area: “Shortly after the eggs were laid, a volcanic eruption may have covered the brood and silicate-rich water infiltrated the preserved eggshells, forming agate.”
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