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Fossilized Shark Teeth on the Internet |
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One environmental agent that can cause long term changes on surface exposed teeth is sunlight. The major change to the fossil is "sunburn" or color fading. We have several teeth in our private collection that must have lain out with one side up for a lengthy period. The exposed side has significantly lighter color in the root and the enamel than the side that was lying on the ground. The half buried teeth we find at Lee Creek, the Nazca desert of Peru and the Atacama Desert of the Chile show this type of alteration. Whether this is desirable is a matter of personal taste. See photo below:
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Another problem for land teeth is the affect of water (rain, ground moisture and high humidity) on the root and dentin. Even teeth a few feet underground can re-absorb moisture. Sometimes this moisture can contain compounds that are detrimental to the tooth. As the rain and surface water makes its way through the humus and topsoil it gradually becomes more and more acidic - chiefly carbonic acid. This acid can leach away (dissolve) the "hard" compounds that replaced the original dentin. Many of the earth's caves are formed in this manner.
When erosion finally exposes these teeth, sunlight and rainwater continue the attack. (Ever hear of "Acid Rain"?) Some Chilean desert teeth are particularly noted for their rotten, chalk-like roots that literally fall apart when picked up. Some collectors will pour a "stablizer" like SuperGlue® on these teeth BEFORE they touch them. Ever wonder why some many Chilean teeth are for sale with the "Bonus" of having matrix attached to one side? It's because the collector poured stablizer all over the tooth and some ran down into the ground underneath the tooth. The excess glue attaches the dirt under the tooth and is almost impossible to remove without destroying the tooth. Now you know!
Land teeth that are lying exposed to the surface can be faced with another destructive problem in cold weather. Rain water that makes its way into the dehydration cracks in the root and the hydration cracks in the enamel can freeze overnight and literally break the tooth apart. This mechanism is responsible for many of the "potholes" in roads in our Northern States. Many phosphate mine and some desert teeth are damaged in this manner when collectors are not braving the elements to gather them.
River bed teeth face entirely different problems. Teeth washed out of the matrix in which they have been buried for millions of years can literally be "sand blasted" by particles suspended in the fast, river current. The main result of this is loss of enamel shine on the side exposed. We have several teeth with a grade 2 shine on one side and a grade 10 shine on the other.
In rivers with fast moving currents the teeth are tumbled end-over-end along the river bed. This causes no end of problems like worn serrations, root ears and blade tips. If the teeth encounter large rocks in their journey, the blade edges, root ears and tips can be nicked and chipped as shown by the edge and tip of the tooth in the photo below:
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Tannic Acid, or Gallotannic Acid [C76H52O46] in some rivers like the Cooper and St. Mary's can color the teeth beautifully in different colors but can also eat away the root and bourrelet enamel.
If these teeth are near the river mouth, saltwater critters can also cause problems. The most benign of these problems can be the attachment of soft coral, barnacles, oysters and tube worms. Due to some mechanism not completely understood, this attachment can change the coloration of the blade and bourrelet enamel. On many teeth for sale on the Internet, this "white stuff" is not completely cleaned off.
See photos below for views of a partial tooth right out of the river (#1) and after the first stage of our 7 stage cleaning process (#2).
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Everyone has seen teeth that have small (and large) holes drilled in the root. This damage is caused by ancient and modern day Borer Clams who make themselves homes in the fossil material. As they outgrow their holes, they emerge and drill a larger home. The tooth below is a classic Cooper River tooth with the rich brown coloration. This particulart tooth washed downstream to end up near the mouth where the salt-water Borer Clams could attack it.
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The last of the environment problems can be caused by the extraction process. Phosphate mine teeth are damaged daily by bucket machines, draglines and bulldozers. If they escape these monster machines, they are subject to being sucked up in the slurry being pumped long distance to the processing plant, banging the interior walls of the pipeline along the way. At the end of this trip they are screened out into the "reject pile". If they still resemble shark teeth in any way they are collected by mine employees.
Another way that we humans damage these teeth is with the aid of picks and shovels. The root ear of this beautiful 4" Lee Creek tooth was damaged in this way. At the moment in time when the blade of the shovel met the root of the tooth, the value went from close to $500 to under $100.
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