One of the most popular questions we’re asked is how to tell if a fossil is fake. Especially to urbanites in a young country with few historical relics, it seems almost mindboggling to be actually holding a specimen that’s millions of years old. This apprehension can be a barrier to starting a collection, and is therefore important to address even though we’ve written about this before.
TYPES OF FAKES
We will start by reviewing the ‘Eight Levels of Fossil Fakery’:
Many fossils coming out of the ground are actually cracked and crumbly, and fossil preparators use Paleobond (basically superglue with different viscocities) to stabilize the specimens. These field repairs are very normal and expected.
In the preparation process, certain parts of the fossil may be missing and preparators may perform restorations, such as carving out and attaching attachments on a spiny trilobite, or filling out a crack in a bone with glue, epoxy, or wax. It is important that an ethical dealer states the percentage of the specimen that is restored, as it significantly affects the price.
Enhancements are often done to an actual specimen, such as painting or polishing the specimen. Although they are still original fossils, such treatments reduce their scientific value considerably but may still be of appeal – not least due to their improved aesthetic value – to some collectors.
Some preparators and collectors may also assemble parts of the same species from different animals (e.g. the digits of a dinosaur finger or claw). Such composite fossils are common and often found in museums, but should not be presented by commercial dealers as 100% complete fossils (e.g. ‘associated’ digits) even though the parts are original.
Large specimens such as dinosaurs are often found disarticulated such as in an ancient riverbed. These original but incomplete specimens may have the missing parts (e.g. a section of the vertebrae or a femur) entirely fabricated in resin or crushed fossil bone, and are known as reconstructions. Similarly, missing Keichosaurus limbs or fish fins are sometimes simply painted in.
At the moment we do not have any qualified paleontologists in Singapore to identify specimens, and in any case sometimes even famous paleontologists make mistakes. It is therefore important to develop your own intuition and expertise and trust your judgement over time. A perfectly-authentic fossil can be mis-identified as another species. This may be an honest mistake or a deliberate way to sell a specimen at a higher price. For example, juvenile Spinosaurus teeth are similar in form to crocodile teeth (only slightly longer) and may be unknowingly misidentified. Raptor or even Tyrannosaurid teeth (sometimes even Carcharondontosaurus teeth) posing as the teeth of T-Rex get higher valuations due to its ‘celebrity’ status. On the other hand, a crocodile skull was recently labelled as a Plesiosaur skull, which is pretty much an outright deception. Rounded rocks with cracks are sometimes unwittingly marketed (and sadly, sold) as dinosaur eggs. Authentic specimens may even be sourced to a plausible yet unfamiliar geological formation or country, just to pique the scientific interests of the paleontology community.
There is also a healthy market of fossil casts. These are spectacular yet affordable items for everyone to collect, and may often be cast directly from a museum specimen (a first or early generation cast). Paleontologists often encourage people to purchase casts, as they generate revenues for museums without depriving the public or researchers access to rare or scientifically-important specimens. It is important that casts be identified as such.
And then there are outright fakes: Fossil specimens fabricated to masquerade actual specimens and sold as such to defraud and profiteer from. These can be fabricated with resin, carved into limestone or even real fossilized bone, or simply painted onto rock matrix or another partial fossilized species. Collectors need to handle as many authentic specimens as possible to acquire an intuition about real or fake, as there isn’t an easy answer to this question.
HOW TO TELL IF A FOSSIL IS FAKE
There exist more robust but expensive techniques such as CT scans, X-Rays, acid tests, radiometric dating using mass spectrometers and fluorine chemical analyses that institutions use to authenticate fossils. However, here are a few general tips for novice collectors to get started:
- Provenance. The information that a specimen comes with is sometimes more important than the specimen itself. It guides prospectors to a locale where more of such specimens may be found, provide useful knowledge to collectors, and perhaps most importantly help to verify the specimen’s authenticity. For instance, is that locality of the right geological age for that species? Does the seller have actual access to the quarry and to his own preparatory lab? Does he have a long and perfect track record (feedback rating) of selling fossils of that category, or have doubts ever been cast on his reputation? Trilobites, Mosasaur jaws, and crocodile skulls from Morocco; Keichosaurus, feathered dinosaurs, and dinosaur eggs from China; as well as ambers with interesting inclusions (e.g. ‘mammoth hair’, lizards, feathers, flowers) are most often faked and worth careful scrutiny.
- Price. On occasion, we see a specimen that may be statistically rarer to find offered for a very low price, such as a feathered dinosaur going for a couple of thousand dollars, or a spiny trilobite (which takes days to prepare) priced at a few hundred dollars. This mismatch of the market value can be a warning sign; when something looks too good a
deal to be true it usually isn’t. Collectors should steer away from a seemingly good deal on eBay, if no one else seems to be bidding on that rare item. This is of course only a guide, as you can always still find sellers putting a very high reserve price of many thousands of dollars on a pebble pretending to be a dinosaur egg. Knowing market price is also helpful as fossils that occur abundantly in nature (e.g. small Orthoceras or Ammonite shells, or even Green River fish) only cost a few dollars anywhere, and is rarely worth the effort to fake.
- Context. We occasionally come across outright rock carvings of animals such as full-bodied snakes with their scales intact, animal “brains”, fruit, phalluses, or gods that may have auspicious value. Collectors with any rudimentary knowledge of taphonomy will know that soft tissue will rarely be preserved intact, yet casual tourists may still purchase these unwittingly. Purchasing from a supplier who has dozens of identical specimens is certainly a sign of fabrication, as every fossil is unique. Mortality plates where multiple fossil specimens or specimens from different geological eras (e.g. Cambrian next to Devonian trilobite species) are assembled together on the same matrix – sometimes in aesthetic circular or auspicious shapes – should certainly be suspect. Animals that are strangely larger in size (or have disproportionate body parts) than the norm should be re-looked at carefully; this is where an experienced eye would be helpful.
- Morphology. Anatomical accuracy is a sure sign, and knowledge of this can only be gleaned with experience and study. Does the animal have symmetry in its body? How do the proportions of its features compare with documented examples? Does it have a missing or extra skull opening? The overall shape, size, and flatness (due to fossilization) of a dinosaur egg can inform if a specimen is truly an egg or simply loose pieces of shell glued onto a base.
Fine details are hard to fake. These include the serrations on dinosaur or Megalodon teeth, growth rings and blood grooves on bone, sutures in a skull, tiny ‘goosebumps’ on a lobster or crab shell, as well as the even and fine spines and schizochroal (compound) eyes on Phacopina trilobites. (Entire industries have been set up in Morocco and China
to fake fossils, and this article offers an excellent exposé on some of the detailed faking techniques for trilobites) Raptor eggs have a ‘leathery’ texture with ridges, and should not be smooth to the touch. Fossilized animal bones and exoskeletons often have spongy parts with fine and deep pores. There is a ‘Lick test’ where unlike rock or fossilized wood, fossil bone is supposed to stick to your tongue (although some of us personally may not enjoy how rocks taste). The positive and negative slabs of a fossil should match perfectly.
- Physical properties. Study surface details carefully, such as changes in material, texture, grain, airscribe markings, or bone pores. Authentic fossils are composed of heavy, compressed rock, and sometimes feature micro-crystals under a magnifying glass or loop. Modern animal bones are sometimes painted, aged, or even attached to rock matrix to look like fossils, but bones are much less dense than fossils (which are essentially rock), and can be discerned by the lower weight and hollow sound made when tapped with your fingernail. The colour on the fossil should be reasonably uniform; teeth that remain light-coloured without veining in the enamel, or darker colours found in areas of greater bone porosity, indicate that the specimen may have been from a modern animal dyed to resemble a fossil. Skull deformation is a sign that the specimen may not be modern. Casts are also much lighter than the solid rock composition of real fossils, although forgers have learnt to attach casts to real rock. Differences in matrix colour may be indicative that a resin cast ha
s been attached to a real rock base. Look out for air bubbles, which form in plaster or resin casts but will not be found in actual fossils. A fake may also have a thin, tell-tale seam running along its sides because the mold needs to be opened to remove casts, although skilled forgers may know to sand these down. We have also come across a matrix base which was betrayed by wrinkles left from the plastic bag that the concrete mix was poured into.
- Damages. Many times fossil prospectors use destructive methods to identify rocks with fossils in them; basically using field hammers to smash the rock. As a result, many fossils – Devonian Moroccan trilobites in particular due to the hardness of the limestone they are found in – often have a repaired hairline crack running across the fossil. This is a good sign that the specimen may be real, but of course no guarantee that it is. Dinosaur eggs always come with shell cracks and indentations as they need to have been buried under considerable mud or sand in the fossilization process; I have never come across authentic dinosaur eggs with smooth shells in some 30 years of fossil collecting.
- Tests. These may be non-intrusive or intrusive. Fossils restored with resin, epoxy, or plastics will glow under a UV lamp, although this may be masked with paint. Composite bone fragments from different sources may show slightly different colour tones under black light. Resin and plastic is also softer than rock, which might be detected with the sensitive nerves of your teeth if you give it a small bite. A drop of acetone can remove paint (useful for modern mammal bones masquerading as fossils) and you just need to look if the colour comes off on the cotton swab, although this would already be considered an intrusive test. Real Mosasaur teeth are often glued into fake roots or jaws (made of crushed matrix) to increase their value, and rubbing with a wet cloth can dissolve this. Taken to an extreme, connoisseurs have used diamond saws to cut a specimen in half to reveal plaster compositions within!Amber is another type of fossil that is often faked, sometimes with plastic, sometimes by inserting inclusions (insects) between actual reattached amber slices, and when confused with copal or immature amber that is only a few hundred or thousand years old. Only amber is warm to the touch and rubbing amber with soft cloth gives off a fragrance and charges it with static, but could start melting copal. Amber will float in seawater or brine (This is how they are washed up in the Baltic Sea) but copals and plastics would sink. Amber is hard and fractures if cut, but plastics can be easily shaved by a penknife. A drop of alcohol, acetone, or nail polish remover will start to dissolve copal, but does nothing to amber. A hot needle easily pierces through copal and gives off a fragrant smell, creates a black spot and smelly fumes with plastic, and does not as easily penetrate amber and produces whitish fumes.
The commercial fossil industry is growing and those manufacturing fake fossils are constantly improving their techniques, so it is best to avoid acquisitions that are at all doubtful even if the price is attractive and to only work with trusted, reputable sources. Beginners should start with affordable specimens to limit their risk, consult the opinion of more experienced eyes, and the very best approach is gain hands-on experience over time by handling wide a range of specimens as possible.
What other useful approaches do fellow collectors use to tell real from fake?