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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.