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Hi, I am wondering what the white globular mineral growths are on this dolomitized Dawsonoceras mold. Calcite? Thanks for any help.

Is dolomite powder as toxic as it states on the bag and should i use more than a dust mask while useing it?

It is in the Changxing island of Dalian, a port city located in NE China, somewhere near Korea. The calcite/dolomites seems to have some scattered trilobites pieces. But the dolomite and clay layers stack up alternatively, which is not supposed to be marine face? BTW, the rocks are supposed to be of Early to Mid Cambrian period. I can not tell the speices of the trilobites. I do not know if they are heads or tails.

There have been some great reports in the last week of folks hunting the Silurian and I wanted to add a report for my own serendipitous mini-trip from the last weekend. A few months ago, I had noticed a large pile of buff-colored stone dumped next to a retention pond in front of a local retail district. I thought they looked very similar to the Silurian dolomite I have seen and collected from elsewhere in Illinois, so I have been meaning to take a closer look. Last weekend I finally had some errands to run at Target with some free time on my hands, so I wandered over to the pile to check it out. In less than a minute I spotted a friendly face poking out of the corner of one piece of stone- Gravicalymene celebra! An iconic trilobite, and the biggest one I have found, with a cephalon just over 1 inch wide. It looks like it may be complete, although prep can be very difficult as @aek mentioned recently- at a minimum the cephalon appears to all be there. I looked around a little more and found a very poorly preserved cephalopod impression as well as one other rock with some intriguing shapes in it- it will need more prep though to say if it is anything. Since these were dumped next to a parking lot and there are no Silurian dolomite quarries within 60 miles, I can't say for sure what the source is. It seems likely to be the Racine or Joliet Dolomite of northeastern Illinois, though. I will definitely be returning when I have some free time and looking around some more- who knows, they may have used the same stone in other spots around the development!

Recently I've been revisiting some local Silurian outcrops. I have a love/hate relationship with these outcrops as they are incredibly difficult to work with, however I secretly enjoy that aspect as well. The fossils represent the Homerian stage just before the Mulde Event, so roughly 422 - 426mya (if I'm not mistaken). For whatever reason, in the Racine formation, Gravicalymene celebra are almost always complete in the molting position and other species usually found disarticulated. The trick is extracting them without destroying them. Sometimes they are found enrolled, though much less common. I have only found two enrolled from this location over the past few years. 1) enrolled Calymene 2) Gravicalymene celebra 3) " 4) " 5) " 6) Sphaerexochus romingeri 7) Pentamerid brachiopod 8) favosites blastoid? 9) Dalmanitid pygidium 10) partial Dalmanites cephalon Close up snaps Sphaerexochus romingeri I believe this is a crinoid cup judging by the shape, but not sure. If anyone has any ideas... and the drum roll... Three species on one plate, Encrinurus pygidium, Dalmanites cephalon and a Calymene on the bottom . Unfortunately, due to the nature of the rock and my lowly prep skills, the only survivor is the Dalmanites. I somehow managed to restore both eyes with the original pieces for a nice "eye-popping" specimen. Thanks for looking . Also, in case you're curious, this entire collection is the result of four trips, not one. About 4-5hours per trip , so about 18-20 hours of collecting. and many more prepping. Cheers

I have been reading through the threads about dolomite powder as a blasting medium for cleaning trilobites. Am I correct in my understanding that to get the range consistenty around 40 microns you need to run the powder through a 325 mesh sieve? I am assuming the dolomite powder available from places like the pottery supply house is not consistently in range of 40 microns, and will need to be sifted. Is there a place to buy 40 micron dolomite than anyone can recommend. (Someplace along the London to Toronto corridor would be ideal) Thanks in advance!

This post is about a well preserved Gravicalymene celebra molt I recently found in the Laurel member of the Salamonie formation of Southeastern Indiana. It is quite a peculiar specimen since it appears to have two very distinct mineral compositions. Most of the trilobite is composed of dolomite as is typical for fossils found in the Laurel. However, I initially noticed what appeared to be white calcitic pieces of the cephalon partially exposed at the anterior end of the specimen. The matrix surrounding these pieces was very easy to remove, having a fine sand like consistency. After some prep work, I was able to uncover a good portion of the glabella and concluded that these white pieces did indeed belong to the same specimen. My initial thought was that they are composed entirely of calcite, but I haven't been able to make that conclusion so I decided to post some detailed pictures in order to see what you all think. Figures 1&2. Specimen in ventral and lateral views. (Before prep work, the white rostral plate and lateral border (cephalic doublure?) which are quite obvious in the above picture, were only partially exposed. Initially my professor suggested that they likely belonged to a separate fossil specimen, perhaps a bryozoan.) Anterior end Figure 3. Anterior view showing the left and right lateral borders (cephalic doublures?), rostral plate and patrially exposed glabella. Figures 4&5. Magnified images of the rostral plate displaying uniform bumpy texture on the surface. \ Figure 6. Magnified image of dolomitized lateral border (cephalic doublure?). Note the absence of the bumpy texture seen in the previous images. So essentially my main questions are: 1. Could this white colored mineral be calcite, or something else? 2. Are the long narrow pieces considered cephalic doublures or just lateral borders? (In my research, I haven't been able to find a detailed description of Calymenid cephalic anatomy) 3. What exactly are the uniform bumps found on the white pieces? 4. Is double mineralization of a single specimen a rare occurrence, or has anyone seen something like this before? 5. What could this mineralization mean in terms of the taphonomic interpretation of this specimen. An interesting side note: A few weeks later I was once again fossil hunting in the spot at which I found the specimen described above. Along with some nice brachs and another full trilobite, I found a partial mold of a G.celebra thorax. I looked and looked for the specimen it may have once been attached to, but was unable to find anything. After returning to my lab, I noticed something quite interesting. It turns out that the mold belonged to the specimen I had collected just a few weeks before! I was glad to have found this mold, since it shows the morphology of part of the specimens posterior half which has been weathered away. Figure 7. The partial mold Figure 8. Specimen and mold side by side. Figure 9. Reunited and it feels so good!

Hello Dear, In the 14th September 2017 I found this armor plate from agnathan and found out that it belongs to Ohesaareaspis, the cephalaspid ostracoderm from Late Pridolian Ohesaaare stage, end of Silurian. I found it it Varena town, South Lithuania, it was in dolomite erratic. Its length is 1,3 cm and it has very interesting surface texture of tubercles. The genus was not identified in Lithuanian (Southern Baltic region) erratics till now, please vote if you are interested. Regards Domas

Dear Guys, I found this fossil in the July 21, 2017 in Varena town, South Lithuania (it is Southern part of Baltic States). The genus of this lungfish is Ctenodus, sp-ecies are not identified. Its age is from Svete horizon to Klykoliai series (Late Famennian- Lower Tournaisian). This genus is still not found in the Lithuania and Baltic States, my find in dolomite erratic is the first dicovery in this region. The length of fossil is 6 mm. Please vote for this fossil if you are interested. Best Regards Domas

I’m wondering if anyone has experience preping stickleback fishes from a dolomite matrix. Obviously it is extremely soft and the preservation is decent but can literally be rubbed away with a breath. Will PVA stabilize dolomite or will it just melt at the introduction of any liquid? A friend gave me a piece to check out and I’d like to stabilize it. Any help appreciated. I can add pics tomorrow if needed. thanks Jeff

I started working on a Mosasaur snout end, and so far it is coming well. I have been running into one issue though with starting to use a sandblaster, and that is that I can't figure out how to clean the extra dolomite off the piece when I am done. I have tried blowing it off with an air compressor, which gets most of it, and using water, which has caused some problems. The water seems to get into cracks and destabilize the matrix, leading to breakage. Any ideas? On this one it dissolved some elmer's glue that was used in a repair, and on some trilobites it broke the matrix. Thanks! Nathan Progress so far.

This morning I met about 12 other members of E.S.C.O.N.I. (Earth Science Club of Northern Illinois) at Irene Quarry in Belividere, Illinois for a quick 3 hour visit. The quarry contains hard rock Ordovician dolomite from the Galena Group. This was my first time at this quarry and though I did not find much, I had a great time with the group and we could not have had better weather. Here are some views of the quarry: Here are a fews pics of my finds: Receptaculites- Receptaculites and Hormotoma- Horn Coral- I believe Strepteasma Brachiopod- At first thought that this was a trilobite Cephalon, but now think it is a brachiopod, looks similar to the brachiopod above. If any one can ID, please do so. One of the collectors found a large cephalopod in a block of dolomite. Here is the large section out of the block- Receptaculites - of course I did not take this one.

Just got my sand blaster in the mail today. I was looking for some powder, not quite sure where you usually buy it. I have heard dolomite is good. I will be prepping trilobites and fish mainly for now. Anyone have a good place to get it, or any other powder recommendations?

I was walking along Lake Michigan with my kids one day last week, and we were examining huge 4 to 5 foot cubes of Dolomite for fossils. We saw a lot of these crystal structures and I'm just wondering if these are calcite or do you think it's crystallization of some fossils of coral or something?

I've noticed that a huge majority of the North American Silurian system is composed of dolomite. During the Ordovician, it seems to me that dolomite formation was sparse, but during the Silurian there is a massive surge of it, and in the succeeding Devonian it seems to have returned to pre-Silurian levels again. What was the reason for this? Is this just a North American phenomenon, or was it worldwide?

So I had a couple of hours today before I had to be at Chicago O'hare airport, so I decided to make a pit stop on the way. I was very happy when I left because I found a trilobite part (yay) can you spot the gastropods?

There are many questions on Dolomite micro-blaster media sources. Here are some links to suppliers and producers for fine ground Dolomite, form a not commonly known source. Base Ball, Football, Soccer, Schools, Etc. The main product used for lineing all of these sport fields is fine ground Dolomite by the hundreds of pounds. I came across a partial bag of this product at a garage sale, cheep. At first I didn't know if I had a use for this 40 LBS of powder, (unknow at the time) but I bought it to check on it. I found out that it is used for marking white lines on ball fields and that it is powdered Dolomite and it worked great in my cheep micro-blaster. Checking the MSDS information from the producer showed that this powder is almost 100% pure Dolomite and if you can find a local source it is only $5 to $10 dollars US per 50 pound bag. Now that is dirt cheep to what many charge for blasting media. The main producer is the Imerys company out of Georgia. Link: http://www.imerys-perfmins.com/usa/markets/field-marking.htm They also have a European branch: Le Choix Des Pros listed on the bag I have. I am thinking that a possable source would be your local school system sports/maintence detartments. They may be able to sell you a bag, order you a bag or give you a name of a local supplier. This might help for someone not close to a supplier as I would think shipping is expensive for a 50 lb. But here are some links for suppliers on line. Better Baseball: http://www.betterbaseball.com/50-lb-bag-of-marking-chalk.html?gclid=CLL838SNp8gCFYM6aQodOvgFUQ JRK seed supply, Diamond White Plus: http://allproturfsupply.com/sportsinfield.html Beamclay.com http://www.beamclay.com/107A%20-%20Field%20Marking%20Chalk%20and%20Dry%20Line%20Marking%20Equipment.pdf Sullivan Corporation; Plus 5, From IMERYS http://www.hellotrade.com/sullivan-corporation/athletic-field-marker-chalk.html I hope this info helps someone to get a cheeper blast medium, and ideas for suppliers of this needed product. Ziggie Cie

Hi. Recently back from hiking trip in the Dolomiti mountains in Alto Adige, Italy. I had discovered this rock. My guide (a geologist) said it was not dolomiti rock, but something earlier. Any ideas?

I was checking out a local creekbed with my husband, and he spotted this interesting rock: I'm wondering if the voids in the rock were originally a calcified coral fossil that weathered away? The rock could be shale, or possibly dolomite. I'm not sure which although shale is far more common around here. Here's a few close-ups of the interior of the voids: This one shows a texture that may have been left by the original organism. Here's a couple where the void is still filled, and the structure of the original organism can be seen. This one has the interior organism in the process of weathering away. Several of the holes go all the way through, some also branch. Others go at least an inch into the rock. That's a bit harder to get a good photo of! Anyone recognize this? Thanks!

So I need help identifying Limestone and Dolostone from each other. I would like to be able to properly id, describe, catalog, etc finds. This also would help me date my finds. From what I know from Wikipedia is basically dolostone, is limestone, that dolomite replaced the magnesium in limestone. Obviously limestone contains high calcium carbonate. Dolostone can come in brown, pink, and white colors. Also I have seen pictures of grey colors as well. This is confusing as what I know as limestone comes in white and grey. Dolomite also crystallizes? Would this make it appear to be more grainy like sandstone? Can somenone break this down to me? Basically articles on the internet just tell me over and over dolostone contains dolomite! Arghh! Lol. Feels like I am banging my head againt a wall! Thanks for your help!!!

Steadly approaching 3 years of collecting from dumped dolomite piles in Milwaukee County has lead to a plethora of "Calymene celebra" molts from Silurian Dolomite of the Racine Formation. Wenlockian. Many hours have been spent with a large sledge hammer breaking out mold of Calymene and other trilobites in similar ways to the Cedarville dolomite in Ohio. The trilobites are almost always complete and are in a noted molting position shown in Weller 1907 An example from my collection and prepped Over the three years we have collected over a hundred complete individuals from the dolomite. About 10 percent of the time we find a Calymene missing its cheeks and in a more flattened preservation. The next most common type of trilobite found is Cheirurus sp. Only 3 complete internal molds have been found of this individual but partials are more common. Likely the species represented here is Cheirurus hydei Found by user evern. As noted this association of trilobites seems to best line up with Hartung Quarry in Milwaukee based on Mikulics Theisis from 1979 on Southeastern Wisconsin Silurian Trilobites. One weird thing is Bumastus being absent from our location, although the chart basically implies only one individual was found. The next trilobites on the list are sparse at best with only a few individuals seen. They are Sphaerexochus, Encrinurus, Dalmanities, Deiphon, Ceratocephala, Acidaspis and Eophacops. The last 4 represented by only 1 specimen each. After finally reading through almost all of Mikulic's dissertation, I am glad to have learned of the location of the stone I have been finding so many trilobites in over the year. Sphaerexochus cephalon Encrinurus Dalmanities Deiphon Eophacops (not mine, Field Museums) Thanks for the read. Hope evern will post his beautiful Dalmanities Cephlon when it is finished prep.

This fossil rock was found in the Mississippian area of Northeastern Trigg County in Western Kentucky. The rock was part of my fire pit.. It was gathered along with others in the pasture area around my home. When we moved the rocks, some broke open and are showing beautiful fossils especially when this rock is wet. It's unusual because on closer inspection, I believe the rock is a mineral and not a rock-rock. What a pleasant surprise Now I want to crack open all the others... lol. This is one of the fossils that was found.