how to clean a fossil
Preparing or cleaning fossils can be done anywhere, from a kitchen table to a high-tech laboratory. There are times when all that is required is a toothbrush and some water. This procedure will remove all of the muck and loose matrix from the fossil, provided that the fossil is robust, such as coral and many brachiopods. Do not make an attempt to brush off your fossil with water if it is delicate, if it has fractures in it, or if it is sitting on soft shale because this could cause it to break. Trilobites, bones, and brachiopods, all of which are fragile fossils, will disintegrate or break apart. To improve the appearance of something that is fragile, you will need to clean your specimen using a different way.
Let’s say you have a trilobite in its entirety and would like to get it cleaned. A portion of it is uncovered but concealed by a thin layer of shale; the remaining portion is entirely encased within the rock.
Miniature pneumatic hammers are going to be utilized in order to unearth the piece of the trilobite that was buried. The pounding of the hammer removes minute pieces of the matrix that were covering up the trilobite in ever-so-slow increments. After the majority of the upper matrix has been removed, the matrix that is in contact with the trilobite shell typically peels off in one piece. It is imperative that the trilobite not come into contact with the hammer at any point.
Prior to the development of micro-airhammers, fossils were unearthed with the help of small steel picks, similar to those utilized by dentists (this technique is still utilized in many laboratories today). The technique is quite effective, as can be seen in the older collections of any museum; but, it takes a very, very long time to do what an airhammer can do in a relatively short amount of time!
Okay, it looks like the trilobite has been completely unearthed, but a very thin layer of shale is still covering it. It is time to get the microsandblaster ready to go. These machines use a great deal of air pressure to propel a very little quantity of powder through a hose and a nozzle onto the fossil. This erodes the softer rock away while maintaining the integrity of the trilobite’s shell, which is much harder.
The air pressure and powder flow need to be controlled, and this can be done through either experience or careful experimentation, such that the matrix can be removed from the fossil without “burning” away the trilobite’s shell along with the rock. Under the watchful eye of the preparator, all of the work is done under a microscope. The preparator is constantly on the lookout for new or previously undiscovered cracks in the shell that will need to be stabilized.
Particular focus must be placed on the eyes. The lenses of the eyes of many species of trilobite are still present, despite the fact that these structures are extremely weak. The entire eye is cleaned using a technique called microsandblasting, which is very sensitive and accurate. This ensures that each lens is perfectly exposed without being harmed.
At long last, the granite itself is polished and made to look better. Either a grinder similar to a dremel tool or a combination of an airhammer and air abrasive are used to remove all of the chisel marks left by the hammers. The matrix has been sculpted so that it presents the trilobite in the most aesthetically pleasing way. During this stage of the process, there are times when fresh fossils are found buried beneath the matrix. These have been tidied up and serve as pleasant surprises that add to the overall piece.
When everything is finished, you may relax and appreciate your trilobite. It is no longer gray and covered with rock; rather, it has taken on a stunning black or brown hue and appears as though it will emerge from the rock at any moment.
Cleaning fossils helps remove excess dirt and debris, making it easier to analyze the fossil. Cleaning also helps preserve the fossil. Cleaning also helps make the cracks and crevices more distinct so that you can experience the full beauty of the fossil you find and plan to show. If you want to display the fossil you found, you should clean it first. You may buy cleaning kits for fossils, but one of the simplest methods to clean fossils is using vinegar. Vinegar, when used appropriately, can also help preserve the fossil if it is cleaned properly.
Put some white vinegar in a bowl or a cup, but don’t fill it up too much. To thoroughly soak the bristles of a toothbrush with soft bristles, dip the toothbrush into the vinegar until it is totally absorbed.
The fossil should be placed on a paper towel or rag, and then the bristles of the toothbrush should be rubbed over the fossil. Vinegar’s acidity will aid in the dissolution of surplus particles, which will result in the fossil’s minute crevices becoming more visible. Toothbrushes with soft bristles are incredibly flexible, making it simpler to maneuver the toothbrush into tight spots.
Re-moisten the toothbrush periodically as you clean the fossil. Using vinegar to scrub the entirety of the fossil can help to preserve it, so make sure to use the toothbrush on all of the surfaces.
If you are working with a fossil that needs a significant amount of cleaning owing to the presence of excessive debris or build-up, pour approximately two cups of white vinegar into a bowl and then place the fossil inside of the bowl. The fossil should be let to soak for around two minutes.
Take the fossil out of the bowl, clean it with some paper towels, and then use a toothbrush with some soft bristles to scrub it in order to get rid of any excess dirt and other particles.
It is just as vital for you to clean and conserve your fossils as it is for paleontologists to find them in the first place. They decay when no care is taken for them, and with each period that passes, we lose a fragment of our collective past. Fossils are some of the earliest pieces of physical evidence that organisms lived millions of years ago. In many cases, fossils are among the oldest pieces of evidence. Therefore, if you follow our helpful advice, you will have a complete understanding of how to clean fossils at home.
In order to ensure that these amazing and uncommon bits of history are preserved in their entirety, you will need to use specialized techniques when preserving and cleaning your fossils.
CLEANING FOSSILS
You are going to require the following items prior to beginning the cleaning process:
- Warm water
- Washing detergent
- Toothbrush or other nylon brush
- Dental tools/pins
- Soft paintbrush
- Microscope (if possible) or a magnifying glass
CLEANING FRAGILE FOSSILS
You will find that cleaning fragile fossils is a bit more challenging than cleaning tougher fossils due to the fact that fragile fossils are delicate and demand detailed concentration. This is because cleaning harder fossils does not require as much attention to detail. When dealing with fragile fossils, such as trilobites, which have hundreds of small crevices, it may be more difficult to access certain parts of the matrix or silt.
The subsequent step is to acquire a gentle paintbrush; nonetheless, it is imperative that you do not use a toothbrush. The abrasive bristles of a toothbrush will leave scratches on the sensitive surface of a fragile fossil that was discovered in shale.
Now, using the paintbrush, carefully scrape off any sediment that may be on the fossil, and then blow it off. To remove any leftover silt, either repeat the technique described above or use a dental pick.
CLEANING HARD & RIGID FOSSILS (CONCRETIONS)
The most effective technique to begin cleaning more durable fossils is to give them a quick rinse in warm water with some detergent.
The next step is to start cleaning any sediment that is still there with a nylon brush, such as a toothbrush with stiff bristles, while the water is flowing. Although this procedure will nearly always be successful with brachiopods, it is not recommended that you employ it because some teeth and bones may be brittle.
It is possible to clean fossils without having to invest in some of the more difficult-to-locate tools by employing a method that is as simple as using a toothbrush. This method is both effective and convenient. At this point, you should be forceful but gentle as you start to extract the dirt and debris from the area.
After the sediment has been removed from the fossils, the following step is to prepare them so that they may be displayed in your collection. This will allow you to make the most of your fossils. Preparing your fossils is the most effective technique to give your collection an appearance that is on par with that of the specimens displayed in museums.
The removal of any leftover silt from concretion fossils typically consists of little more than a simple soak in water and detergent. Again, because we want to preserve the layer of mother of pearl (nacre) on the gastropods and ammonites, you should avoid utilizing water that contains these organisms. As a result, the fossils will have the appearance of having been meticulously cleaned and will be prepared for display.
CLEANING AT HOME
Before the carefully unwrapped specimens can be studied or presented in an appropriate manner, they will need to be given a bath or subjected to a more in-depth cleaning. The process of collecting fossils is made more difficult by this step. Many amateur collectors are mystified as to why the specimens on display at museums are so crisp and detailed, while the appearance of their own specimens remains murky. The solution lies in the preparation, or the lack of it, on the part of the individual. The clinging matrix can be meticulously removed by hand or with machines by museums, which engage full-time preparators to do the work.
The cleaning process for some specimens will consist of doing nothing more than soaking them in warm water with a dash of soap, then scrubbing them with an old toothbrush, and finally rinsing them in clean water to remove any residue. This category contains specimens that have become detached from soft shales as a result of weathering. In addition, shark teeth and shells dating back to the Miocene or Eocene have been discovered in sandy matrix along both beaches. Concretionary fossils, which include ammonites, bones, crabs, and fern fossils, break to a clean surface and, in most cases, do not require any additional treatment other than washing or brushing to remove dust.
However, the vast majority of fossils require additional cleaning, even if they appear to be free of matrix at first inspection. Matrix is invariably encased in brachiopods and can be found stuck in the hinge line. It would appear that trilobites’ corrugated skeletons have concrete packed in the ridges and valleys of their structure. Crinoids have to arrange their thousands of feathery appendages. The apertures of the snails are covered with rock. Bony fossils are preserved inside of a rock casing; but, by the time the bones have weathered and become exposed, they have been reduced to bone meal. In every one of these scenarios, the removal of hard matrix is required.
Soaking and Scrubbing
Before anything else, you need to wash all of the hard fossils with soap and water. Hard fossils are long-lasting specimens that are not attached to a matrix of soft shale or sandstone that is prone to dissolve when exposed to water. Additionally, hard fossils are not comprised of thin, delicate films that have the potential to come apart when exposed to water. These tiny specimens include things like graptolites, plants that have been carbonized, and arthropods with thin shells. Experiment with a damaged sample if you are unsure what to do. Some fossils, like the brachiopods that can be discovered in shale as individual shells or valves, are so fragile that they disintegrate when the adhering shale that was holding them together is released by water.
When you need to scrub a fossil, the best tools to use are compact nylon brushes like toothbrushes. Limestone and shales that have been eroded over time are sometimes completely removable.
Trilobite Elrathia kingi photographed in Utah’s Wheeler Amphitheater. Brush and water were used to clean the sample that was found in the shale. Cambrian period.
through the use of a light yet persistent scrubbing motion. Nylon is not as brittle as the calcite that is found in fossils, and it is also not as brittle as the matrix. It only removes matrix grains that have become dislodged due to weathering. The brushing motion has no effect on new, hard limestone or shale. Sometimes the matrix can be loosened up by soaking it in water for many days.
If the matrix cannot be removed by scrubbing, place the specimen aside so that it can be mechanically prepared.
Specimens that have been stained can occasionally be removed of their stains by immersing them overnight in a sodium hypochlorite solution (such as Clorox). Always start by testing this method on a small sample piece. In the event that specimens have been contaminated with natural crude oil or asphalts (some Silurian fossils from northern Illinois and Indiana have been discovered in this state), submerge them in gasoline for a whole day outside, scrub them with a brush, and then rinse them multiple times in gasoline that has been purified. Avoid using brushes with plastic handles, such as toothbrushes, because gasoline will cause the plastic to weaken. Before bringing the specimens inside, let them air for at least a day or two outside first. Do not get rid of the soiled gasoline by pouring it down a drain since the fumes could explode. Kerosene or light oils, and even the most powerful detergents, are not as satisfactory as gasoline, since gasoline will penetrate the specimen, remove the crude oil, and then totally evaporate. Kerosene and light oils, as well as the strongest detergents, are not as satisfactory as gasoline.
Wheeler amphitheater, located in the House range in Millard county, Utah, is notable for the abundance of fossils in the shale beds and limestone strata there. (Image courtesy of Dwayne Stone)
It is impossible to use water to clean specimens that are on the surface of soft shales. The shale will become bloated and then violently erupt. The easiest way to harden these shales is from the rear using the hardener that was discussed earlier. The fossil itself can be cleaned by cleaning it gently with a cloth or paper towel that has been soaked in rubbing alcohol. Make every effort to prevent the alcohol from penetrating the matrix. After the specimen has been well cleaned, a brushing all over with the hardener will protect the surface of the specimen and make it waterproof.