Internal cast fossil of maybe a Syringothyris sp. brachiopod found in Washington County, Indiana. It might be from the Spickert Knob Formation (Borden Group) of the Mississippian Period. According to the Indiana Geological Survey, this formation is wedged between the Edwardsville Formation (above) and New Providence Shale (below). The formation this fossil was found correlates to the Keokuk Limestone. Thanks to my cousin for this fossil specimen.
Identification resource used is the Indiana State Museum collections database. In particular specimens 71.1.7234, 71.1.11021, and 71.1.11022.were used as similar fossils. Note two of the specimens were identified down to the species as Syringothyris texta.
This Dalmanites sp. trilobite cephalon fossil was found in the Waldron Shale of Clark County, Indiana. This trilobite existed in the Silurian Period. The fossil was prepped with sand abrasive cleaning. Unfortunately, I got too aggressive with cleaning and part of the shell was removed. The fossil is upside down and crushed. It could be a molt. The cleaning did reveal the eye and its lens. Thanks to my cousin Kenny for cleaning the lens area allowing a lot more detail to be seen.
The picture below is of the fossil before prepping. The eye on the right is covered in matrix and the left one is filled with rock.
Next picture of an intact Dalmanites limulurus trilobite of the Rochester Shale Formation of New York.
Bob Schacht's website has two very, very nice Dalmanites halli fossils from the Waldron Shale of Shelby County, Indiana. As described on the site, "simply stated, maybe the best Dalmanites ever to be found in the Waldron Shale Formation." Judge for yourself by seeing the page here.
Want an intact Dalmanites fossil for yourself? As of this writing, one can buy one for about $175 US at the Indiana9Fossils site: Dalmanites Trilobites page.
Being a curious cat, I decided to investigate sand mold metal casting. Previous work installing a new water heater for my aunt left quite a bit of silver-tin solder droppings from working on the copper pipes. After reading a post by T-Rexy at the artistic dot dot dinosaur blog showing silver trilobite jewelry by Billy's a Bad Kitty, it made me wonder if I could make silver fossil replicas. I used silver-tin solder scraps for my experiments trying to mold fossil shapes in metal. In the end, silver metal clay is the material that should be used instead of trying to recycle plumbing solder. Below shows an attempt to replicate Turritella gastropod fossil from Alabama.
First, when dealing with flames or soldering irons remember safety is the priority. During my metal working, I wore safety glasses and had on thick leather gloves. In addition, I worked with the metal inside a grill and used thick rocks and metal trays with sand as a medium to hold the molten metal. Extreme caution was used when dealing with this hot material and tools!
One of my molds involved the Silurian Period brachiopod Stegerhynchus? from the Waldron Shale of Clark County, Indiana. The first picture shows a result and you can see the pits made by grains of sand, maybe they can be polished out? A picture below shows the actual fossil and its silver-tin replica.
I next tried the Phacops rana trilobite from the Jeffersonville Limestone of Clark County, Indiana. A few things became obvious at this point, detail gets lost in the sand and metal replica gets a lot smaller than the original.
My last set of images show an experiment using a Flexicalymene trilobite from the Ordovician Period. I used plaster to make this mold because the fossil is small. As you can see, the plaster got some what scorched while melting the metal.
UPDATE: (07/04/2010) The Dry Dredgers of Cincinnati generate some great YouTube videos and one of them is of a member who did some lost wax castings of fossils using brass. Included in this post is the link to the video:
As a side experiment inspired by Theodore Gray's column at Popular Science on how he burned diamonds. I do not have any diamonds plus it appears quite dangerous to burn them. Instead I wanted to try and melt fluorite after reading it is used as a flux for steel making. So I tried it and found that fluorite crystals sort of just explode like a kernel of popcorn in the microwave. Suspecting this might happen I had metal shielding between me and the crystals I was working with. Now I wonder if they grind the fluorite into a powder and then try to melt it? More research needed...
