| Fossils and How to Etch them |
The fossils this article is about are from Northern and central Utah. The ability to etch these fossils very from one specimen to another and I have no knowledge of how well fossils from other geographical areas will etch. The fossil bearing rocks from northern and central Utah were limestone or a mixture of limestone and sandstone. I found that rocks containing large amounts of sand mixed in with the limestone were much harder to etch than the pure limestone. The difficulty to etch the limestone was proportionally harder as the sand content increased. Watching a fossil slowly emerge from the darkness of a stones interior into the daylight after being hidden for eons is almost a spiritual experience. You are freeing a fossilized animal from its stone walled dungeon where it was imprisoned for perhaps millions of years. Finally they are able to bathe in the light of day for the first time in a long long time. Here is the method I use to etch fossils. Lime stone can be dissolved using Muriatic acid, (Hydrochloric acid). This is not to be used by children and of course eye protection is a must. It would be a good idea to keep a concentrated solution of baking soda hand to neutralize any accidental exposures or spills. A set up like the one shown below is ideal. If you don't have access to a burette and if you are handy it is not very difficult to rig a simple dripper with a funnel, some fish aquarium tubing that tightly fits the small orifice of the funnel and a pair of clamps to control the drip rate. |
