In 1883, what was believed to be a decorative crystal gemstone was cataloged and placed in the mineralogy collection at the Natural History Museum in London.
Found in central India, the agate, as it was called, was almost perfectly spherical, around 6 inches across and a light pink color.
Although beautiful, the stone was “not thought to hold much other significance,” according to a March 29 news release from the Natural History Museum.
That was until Robin Hansen went to a mineral show.
Hansen, one of the curators of the mineralogy collection, traveled to France shortly after placing the museum’s agate on display in 2018.
“While I was looking around the show, a dealer showed me an agatized dinosaur egg, which was spherical, had a thin rind, and dark agate in the middle,” Hansen said in the release. “That was the lightbulb moment when I thought: ‘Hang on a minute, that looks a lot like the one we’ve just put on display at the museum!’”
Hansen decided to talk to some dinosaur experts.
She spoke with paleontologists, and they agreed that the agate was the right size and shape to maybe be an egg, and the stone showed evidence that it had once been pressed against other spherical rocks, just like a clutch of eggs in a nest, the release said.
After a closer examination, the researchers saw that the agate was lined by a thin white layer, likely an eggshell.
“It was identified and cataloged correctly as an agate in 1883 using the scientific knowledge available at the time,” Hansen said in the release. “It is only now that we have recognized that this specimen has something extra special — the agate has infilled this spherical structure, which turns out to be a dinosaur egg.”
The egg’s discovery
The egg was first collected sometime between 1817 and 1843 by a man named Charles Fraser who was living in India during that time, according to the release.
It means that the egg was collected “at least 80 years before dinosaur eggs were first scientifically recognised,” the museum said.
Dinosaur eggshells weren’t confirmed to still exist until 1923, according to the museum, when an entire nest was found in Mongolia.
It may have even been collected before the word ‘dinosaur’ existed, since the word wasn’t defined until 1842, according to the museum.
The timing of the egg discovery means it may be the first dinosaur egg ever found — and they didn’t even know it.
Based on the age of the egg, and where it was found, the paleontologists believe it belonged to a titanosaur, Earth’s biggest dinosaur, the release said.
Life as a Titanosaur
Titanosaurs lived from 163.5 million years ago until around 66 million years ago, according to Encyclopedia Britannica, and could grow to heights of 85 feet, making them the largest terrestrial animal ever known.
In comparison to their large size as adults, their eggs were surprisingly small, as seen by the inches long agate from India.
“It seems really weird because these would’ve been huge animals,” paleontologist Paul Barrett said in the release, “but what they were doing instead is laying a lot of eggs. Many living animals we know use this trade off, in which they either invest in a small number of larger eggs or a larger number of smaller eggs.”
“It looks like titanosaurs adopted a strategy of laying large clutches of about 30 or 40 smallish eggs,” he said.
Paleontologists also believe that dinosaurs regularly returned to volcanic regions to lay their eggs because it was warm, the release said.
“This would also help explain how the egg agate formed,” the museum said. “It’s possible that shortly after a titanosaur laid its eggs in the warm sands, a nearby volcano erupted.”
The volcanic rock would have covered a dinosaur nest, and then it would have solidified, leaving the egg intake within the stone, according to the release. The embryo would have rotted away, and the water, which was full of silica, would have filled the space, eventually solidifying into the beautiful pink stone seen today.
Sixty million years later, it was dug up in India and brought to London.
The egg and other specimens are on display at the Natural History Museum in London as part of the “Titanosaur: Life as the Biggest Dinosaur” exhibit.