If you’ve ever dreamed of walking with dinosaurs, getting close to those massive creatures is easier than you might think. It just takes a trip to a nearby gallery or auction house where you can buy the fossilised remains of a creature that lived many millions of years ago.

What’s hot, what’s not

Before you buy fossils, take note.

What’s hot: Entire skeletons especially those of Tyrannosaurus rex along with European Wooly Mammoth tusks, both in good condition.

What’s not: Fossil shark teeth have no financial value.

You will have lots of company, however.  Private collectors, as well as geology buffs and even dinosaur-crazed 12-year-olds are zeroing in on petrified wood, fossil teeth, and even complete skeletons. While a complete Tyrannosaurus rex skeleton can command seven figures, an authentic fossil shark tooth can be had for only about $5.

Some dealers claim this material is “investment worthy.” But is it? Should you scour dusty gift shops at famous dinosaur dig sites or eBay to find fossils to sell for a much higher price? Or should you just let your children pass around your chunk of amber without worrying about it being dropped? In short, are fossils treasures… or trinkets?  BBC Capital has some answers.

Growing demand

Fossils are traces and remnants of organisms dating from the Prehistoric Age. That’s a daunting 50m to 700m years ago. Some enthusiasts find fossils beautiful, while others love the science.

Popular culture also drives interest, said Bob McNamara, the owner of fossil retailer Paleo Direct Inc in Altamont Springs, Florida. Demand for fossils often spikes after the release of movies such as 1993’s Jurassic Park, and museum shows, such as the 2014 exhibition, Pterosaurs: Flight in the Age of Dinosaurs, at New York’s American Museum of Natural History.

Examples dating from the Prehistoric Age are garnering attention internationally, though it is impossible to determine exactly how many people collect fossils. “Private collectors are growing in number like never before,” said Thomas Lindgren, co-consulting director of the natural history department at auction house Bonhams in Los Angeles. Collectors throughout the US, UK, Europe and the Middle East to clear across Russia and Asia are vying for dinosaur eggs, early lizard-like reptile skulls and entire skeletons, he added.

 “In the past five years alone, I’ve seen the number of collectors quadruple,” said Lindgren, who also owns a fossil gallery, GeoDecor based in Tucson, Arizona. “They come from a number of professions including academia and just plain folk.”

Spurring collecting for certain types of fossils are some museum shows.  For example, the Natural History Museum in London is headlining Mammoths: Ice Age Giants, which opens 23 May. That exhibition, which originated at the Chicago Field Museum of Natural History is helping drive interest in Mammoth skeletons and tusks.

At the same time, the supply of Mammoth tusks is increasing. In the past few years, Siberian mammoth tusks, often longer than ten feet, have been unearthed from islands off the Arctic Coast, making them more freely available for private collectors on the open market, with the strongest demand coming from China, where the tusks are used for ivory carvings that fetch more than $1m, according to experts.

The appeal

For many enthusiasts, fossils are a link to a vanished past.

“They’re an early sign of life,” said Donald Phillips, president of the New York Paleontological Society.  “After all, dinosaurs ruled for 135 million years so it’s a story about evolution and science.” Phillips has also amassed a personal collection of more than 200 examples.

The uptick in interest from novice and seasoned collectors alike is driving demand.  And that has an immediate effect on the market.

In some cases, material is scarce. “With door closing on the supply and demand shooting up, values are soaring,” said John Issa who heads up Canada Fossils Ltd in Calgary, Alberta. “A saber cat skull 20 years ago cost $20,000. Now it’s north of $485,000 and higher,” he said.

Most coveted

T. rex fossils are “king” when it comes to collecting, said Issa, who is also vice president of the Association of Applied Paleontological Sciences in Logan, Utah, which is made up of dealers, academicians, and collectors to promote ethical collecting. “I get requests weekly for T. rex skeletons, bones and teeth.”

A while back, Lindgren sold a 40-foot long T. rex skeleton to a private collector in Southern California for $5m. The skeleton required 54 crates. A genuine T. rex tooth can be purchased for $1,000, said Merv Feick of Indiana9 Fossils in DeSota, Missouri.

 “The real crown jewels are European Wooly Mammoth tusks from the last Ice Age,” said Paleo Direct’s Bob McNamara. “A pair can go as high as $485,000.”

On the less expensive end, a cast of a gingko leaf can run only $80. A fossil shark tooth costs as little as $5 at The Evolution Store in New York City where sales are brisk. They are not rare and are unlikely to appreciate in value, experts said.

Ammonites are also relatively inexpensive. These extinct molluscs date from 71 million years ago and are “the great, great grandmother of squids,” said Issa. “Collectors are drawn to their beauty with pearly iridescent colours.” A small brooch with an ammonite sells for about $300, while the finest examples sell for $100,000. 

What to look for

The difference between a fossil treasure or a trinket depends on its condition and what it contains.

The value of fossil teeth “depends on the type of fossil, the size and the condition,” Issa said. The value of amber (fossilised tree resin) is determined by size and, in some cases, the rarity of the insect or fern embedded inside.

Ammonite values also vary.  “Colour, brightness and condition make for a treasure,” Issa said.

Novice and seasoned collectors alike should use caution when purchasing online. “Thousands of fakes are sold on eBay,” said George Winters, AAPS administrative director. Trilobites, which include centipedes, scorpions and insects (there are more than 20,000 species), are a major cause for concern. Fakes are often made of plaster or epoxy or heavily restored. In addition, many partial and entire skeletons are composites, which are comprised of portions of bones from multiple dinosaurs and often fossils that appear authentically old have been carved from stone and are fake, he warned.

The bottom line

For the greatest long-term appreciation, collectors should seek whole bones or skeletons, which are likely to keep their value better, and ask for authentication, he said

“Buying fossils is just like taking on a used car, you want a trusted dealer,” said McNamara. Fossils should be unconditionally guaranteed to be genuine, legal and properly identified, he said. Collectors should be sure they have the correct fossil type, and also note the condition and the amount of restoration.

To get help with identification, head to a museum such as the AMNH Division of Paleontology in New York or AAPS member dealer. The AMNH even has an annual identification day devoted to correct identification of examples, Phillips said. In 2014, it will be held 10 May. Other museums to seek out include the Field Museum and the London Natural History Museum.

Check with AAPS dealers to determine the country of origin to avoid buying fossils that have been illegally taken from their country of origin and sold through the black market. Material from China should be avoided as that country prohibits exporting fossils, Winters said.

Even though more collectors are becoming increasingly savvy, legitimacy is still an issue, said Winters.  “More fakes are coming out of China and Morocco,” he said, adding, “Ask for a full description and get a guarantee of authenticity.”