Fascinating Fossils

Rock hounds and treasure hunters flock to the dry outback of eastern Australia to search for opals. About 95 percent of the world’s supply of these shimmering rainbow-colored gemstones come from the country’s opal fields. But some of the luckiest opal hunters will find something even more exciting: dinosaur fossils that have turned into opals! One of these opal fields, known as Lightning Ridge, has the greatest number of opalized fossils in the country—as well as the most diverse collection of fossils. 

“It has been said that only one bone in a billion becomes a fossil,” says Elizabeth Smith, a paleontologist who has studied the site for years. “And opal is incredibly rare. So what are the chances of finding a dinosaur bone that has turned into opal?” Yet thousands of opalized fossils have been found at Lightning Ridge, including those from turtles, mammals, and giant marine reptiles. Many of them have yet to be studied. 

Rock hounds and treasure hunters flock to the dry outback of eastern Australia to search for opals. Opals are shimmering, rainbow-colored gemstones. About 95 percent of the world’s supply comes from this country’s opal fields. But some of the luckiest opal hunters will find something even more exciting. Sometimes, they find dinosaur fossils that have turned into opals! One of these opal fields is Lightning Ridge. It has the greatest number of opalized fossils in the country. It also has the most diverse collection of fossils.

According to Elizabeth Smith, only one bone in a billion becomes a fossil. She’s a paleontologist who has studied the site for years. “Opal is incredibly rare, so what are the chances of finding a dinosaur bone that has turned into opal?” Lightning Ridge seems to defy the odds. Thousands of opalized fossils have been found there. They include fossils from turtles, mammals, and giant marine reptiles. Many of them have yet to be studied.

These rare opalized fossils formed when water rich in the mineral silica soaked into pinecones, shells, and animal bones “like jelly in a mold,” explains Smith. “Then it slowly dried out and hardened into opal.”

Dinosaurs and other creatures roamed Lightning Ridge 110 million years ago. It was on the edge of an inland sea. Mud from the rivers and lakes that flowed into the sea was packed with silica from volcanoes. As these waterways dried out, says Smith, conditions were just right to form opal and opalized fossils.

Many of the opalized fossils discovered at the site were found by miners digging for the valuable gemstones. In the past, the miners would cut the opalized fossils into smaller pieces in order to sell them for jewelry. Fortunately, today many of the fossils are donated to museums for the public to enjoy and scientists to study.

The Australian Opal Centre in Lightning Ridge is home to the greatest collection. It contains more than 4,000 fossils worth an estimated $3 million. Researchers like Smith hope to continue studying and identifying the fossils found at Lightning Ridge. Experts say these fossils could result in doubling the number of known Australian dinosaur species.

These rare fossils formed when water rich in the mineral silica soaked into pinecones, shells, and animal bones. Smith compares it to jelly setting in a mold. “Then it slowly dried out and hardened into opal,” she says.

Dinosaurs and other creatures roamed Lightning Ridge 110 million years ago. It was on the edge of an inland sea. Mud from the rivers and lakes that flowed into the sea was packed with silica from volcanoes. As these waterways dried out, says Smith, conditions were just right to form opal and opalized fossils.

Many of the opalized fossils were found by chance. Miners that were looking for regular opals found them while digging for the gemstones. In the past, the miners would cut the opalized fossils into smaller pieces. They’d then sell these pieces for jewelry. Fortunately, today many of the fossils are donated to museums for the public to enjoy and scientists to study.

The Australian Opal Centre in Lightning Ridge is home to the largest collection. It contains more than 4,000 fossils worth an estimated $3 million. Researchers like Smith hope to continue studying and identifying the fossils found at Lightning Ridge. Experts say these fossils could result in doubling the number of known Australian dinosaur species.