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I’ve been interested in biogenic influences on minerals for a while. I have a large collection of stromatolites/oncolites/microbial mats etc. where algae influenced the minerals. I also have hot spring and cave minerals that were also influenced by biogenic processes. However, a new book, shown below has opened up a whole new class of Biominerals mostly influenced by nano bacteria. A lot of the theories in this book are at the forefront of science and are not yet mainstream or even accepted in some cases. However, I thought it was definitely worth a few posts here on TFF. Marco Campos-Venuti 2022 Biominerals microbial life in Agates and other Minerals (526 pages): I’ll start with some biogenic influence examples in agate. The below figure is from the book. Note although the figure talks about agate, a lot of the examples are really in jasper and not agate. Campos-Venuti goes into detail about the processes that lead to these geometries but I don’t want to get too wonky for this post. Below are a few specimens from my collection which demonstrate each of the five geometries of bacteria colonies from the figure. My friend who told me about this book warned me that if I bought the book, I would most likely be buying a lot more, different specimens. He was definitely right. 1. Laminated (truthfully I find this the hardest of the geometries to really distinguish in a piece) I have a number of pieces of Lavic Siding Jasper. Pictures of one are shown below (Note I still have to sand and polish this piece.) You can see a brecciated laminated structure. : Lavic Siding Jasper slab, Mojave Desert, California (186 grams 5.75x4x.25 inches) 2. Dendritic (Dendrites are really easy to see in minerals, although not all dendrites are from biogenic influences) I have lots of dendritic examples in minerals. A lot of dendrites are not biogenically influenced but the result of crystallization. So to be sure, I’m using a specific type of material that is from an area that Campos-Venuti specially uses as an example in his book. Sonora Dendritic Jasper slab, Mexico (136 grams 4.125x3x.31 inches). 3. Lumpy or reniform Campos-Venuti hasn’t really identified many examples of this geometry. I have two different pieces of King Cobra Jasper from India shown below. King Cobra Jasper Slab India (180 grams 7x3.25 inches 7mm thick): King Cobra Orbicular Jasper Slab, India (208 grams 4.5x4.75 inches x5.7mm): 4. Flame There are a lot of really nice examples of biogenic flame influences. Below are two difference pieces from Mexico. Flame Agate end cut, Mexico (335 grams 4X2X2 inches): Flame Agate Slab, Chihuahua, Mexico (668 grams 5.75x2.25x2.625 inches): 5. Plume There are a lot of really nice examples of biogenic plume influences. Below are two different small pieces from Oregon. NorthRidge Plume Agate Slab, Owyhee Mountains, near Homedale, Eastern Oregon (27 grams 2.25x1.5x.125 inches): NorthRidge Plume Agate Slab, Owyhee Mountains, near Homedale, Eastern Oregon (22 grams 2.25x1.45x.125 inches) I hope this post may have increased both an understanding of biominerals, biogenically influenced minerals, and an interest in them. Marco Sr.
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- biominerals
- agate
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Going through my bucket of unknowns and no better way to describe this. Found in creek with mix of Cretateous and alluvial deposits. Originally thought it was wood, not so sure now, I've never seen these spots before that look like they're floating. So tiny hard to get clear pics of the white spots that look like a flower opening and some of the spots appear to be holes at the surface. Must be biological in nature I'm thinking but what? It's pretty whatever it is.
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I was taught that this is jasper. Ouachita river, central Arkansas. But could this also be like petrified wood jasper? Is there such a thing and am I far from identifying this correctly? Your knowledge is greatly appreciated.unlike other similar jasper I have found, this has a golden sheen. (?)
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Crinoid calyx or echinoid? Found in gravel with Ordovician-Devonian fossils. About 2cm across at the widest point. Druzy coating over the fossil which seems to be an external mould. In orange jasper. Thanks so much!
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- ordovician
- silurian
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I found this piece while walking along a building in Northern Germany...first I thought, "Huh?...this looks out of place"...I thought it was just a weather-worn veiny stone...Then I picked it up, saw the fractures and thought, "Wow!, what a nice piece of Chert or Chalcadony (va. Jasper) what are you doing here?"...The fractures are heavily weather-worn, conchoidial, opaque and with a dull luster... After a while I began thinking that the shape, weathering and banding/striping was a bit unusual (mostly opinion at the time)...I wondered if it might be a fossil...a big Brach maybe? Photos courtesy of the Google ...unlikely After seeing close-ups while cropping the pics to post here, I thought, "Hmmm...I got wood?"... It kinda looks like petrified bark to me now, but its "grainy or veiny" on both sides, which seems strange, to me, for a piece of bark... Probably purely geologic combined with wishful thinking...it happens...although, if it is geology, it would be cool to come across a Genisis Jasper where it should not be Photos courtesy of the Google ...ooops...doin' it again...sry Anyway, either way its a beautiful specimen with an interesting story... Any ideas or opinions?...thoughts will be greatly appreciated...thanks in advance... Have a nice day
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- petrified wood
- chalcedony
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Found in Michigan LP. Devonian age probably? Loads of corals and other agatized fossils wash up on that beach. This is the only one I’ve found like this.
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- trilobite?
- michigan
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Went to the local gravel pit. Walked away with this gorgeous gastropod and a beautiful bryozoan in jasper. Will be returning
SilurianSalamander posted a topic in Fossil Hunting Trips
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Found this in the ‘Golden Gravel’ in our garden. Source unknown as it was here when we moved in and rock ID’d (using an app) as Yellow Jasper. The closest thing I’ve been able to find for the fossil is Hamulina or Toxoceras (last image), but not been able to find any mention of this being found in Jasper. Any ideas?
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I've noticed that despite finding loads of petrified wood deep in East Texas (around Jasper, just east of Lake Sam Rayburn), I've never heard of any vertebrate material being uncovered in the area. I specifically spend a lot of time hunting petrified wood on the catahoula formation ( which is Oligocene) when I'm there, and there's definitely no shortage of said petrified wood. If so many trees are fossilized, shouldn't there be fossils of the animals that lived along side them too?
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Hello TFF, I purchased this relatively inexpensive specimen at Mineralfest this past fall, and I was wondering if anyone could tell me more about it. The seller informed me it could possibly be from Madagascar, but was transparent in admitting that she couldn't confirm for sure. It was with other pieces of petrified wood that were brown, but I was drawn to this one due to the red hues. I think it's agatized, and it looks "glassy," although there are too many impurities to shine a cell phone light through it. One side is polished, and I put water on the rougher backside to show more of the details in the coloration. When I went to research the process of identifying tree species from petrified wood, I came across high powered microscopes that could identify structures on a cellular level. I don't have access to that sort of technology, but I was wondering if anyone has any guesses as to what the species could be, how old it might be, what it might be made of, or any other information that could be gathered from looking at the specimen. I'm always curious about what the prehistoric "story" could be behind a fossil, or anything related to the unique biology of ancient life. Thank you for your time, and your knowledge is greatly appreciated!
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- fossil identification
- red agate
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From the album: Platteville to Decorah formation Ordovician Twin Cities
Yesterday I went on first fossiling trip of the year. Its one of a pretty small timeframe in which I am able to accessible certain sites as thaws are happening but marshlands are frozen. Two years in row found a sizable agate in very different locations - last year was on a sandy road recently constructed up north Minnesota. This agate (right side) is hardly chipped. The left side is typical twin cities glacial deposited japser - certain sites far north Minnesota produces superior quality jaspers by compare. This one is much more smooth on one side and more redder than usual-
- minnesota
- lake superior agate
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Hello everyone, I found this in Washington State, Pleistocene, near Mason County. Suggestive piece of jasper or fossil bone? And I apologize for not using metric. I couldn't find my other measurer... Your thoughts would be appreciated. Chris
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- jasper
- fossil bone
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I am not sure what it is. Maybe Stromatolite? Dense piece. The coloration looks like it with the red.
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- stromatolite
- jasper
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From the album: Naughtistic fossils and rocks
Another picture of a chunk of jasper -
From the album: Naughtistic fossils and rocks
One of many pieces of jasper I collected on The North Saskatchewan River