A rare fossil discovered in Oklahoma is making waves across the paleontological community after a geology professor and his student unearthed what could be one of the oldest known examples of a gemstone-quality ammonite fossil.
A Glimmering Surprise Before Spring Break
Just ahead of spring break, Dr. Chris Shelton, a geology professor at Rogers State University (RSU), took his student Kolby Dooling to a familiar site known for its fossil deposits. While the location had yielded discoveries before, nothing had prepared them for the extraordinary piece Dooling brought back that day.
“Just before spring break, I took one of my students, Kolby Dooling, to a site that I’d taken other students to before, one that had always been a good place to explore,” said Shelton. “We’d noticed these fossils before, but this time, Kolby brought a very large iridescent piece to me. It was clear he had discovered something extraordinary with this ammonite fossil.”
Gemstone Fossil From The Depths Of Time
The fossil belonged to an extinct group of marine mollusks known as ammonites, close relatives of modern-day squids and octopuses. But this specimen stood out. It shimmered with the vibrant colors of a gemstone—a quality attributed to its mineral composition.
The preserved shell retains a mother-of-pearl luster due to the presence of aragonite, a mineral known for its light-diffracting microstructure. This brilliant feature suggests the fossil may qualify as true ammolite, a rare and valuable gemstone better known from Alberta, Canada.
“Ammolite is very unique as it’s a biological gemstone, similar to pearls, formed from the fossilized shells of ancient cephalopods—mollusks related to modern squids—that exhibit vibrant, iridescent colors and patterns due to the microstructure of the original aragonite,” explained Shelton. “They’re particularly rare and sought after by collectors.”
Predating The Dinosaurs
While most known iridescent ammonites come from the Mesozoic Era, the age of dinosaurs, Shelton’s fossil goes far deeper in time. This specimen dates back to the Carboniferous Period, over 300 million years ago—long before even the first dinosaurs had emerged.
Its discovery marks an exception among known fossils of this kind, which are usually found in much younger geological layers. Until now, only one other site—the Buckhorn Asphalt Lagerstätte in the Arbuckle Mountains of Oklahoma—had produced aragonite fossils from this era.
Expanding The Search For Ancient Brilliance
Following their discovery, Shelton and Dooling returned to the site and uncovered more fossilized remains, including ancient shark material and invertebrates. Their goal now is to run detailed analyses and publish their findings in a peer-reviewed journal.
“We plan to do more expeditions, more collection trips to the site to gather more samples,”said Shelton. “From there, we’ll run many more analytical tests on the fossils to confirm our belief and based on the findings, Kolby and I will write and submit a peer-reviewed paper for acknowledgement of our discovery within the scientific community.”
For Dooling, the experience has been nothing short of transformative. Shelton emphasized the importance of hands-on discovery for students: “It’s always good for me to take students out of the classroom and into the field, from the theoretical to the practical, to find fossils for themselves and to get to uncover their own piece of history.”
