choochoorocks
starting to spend too much on rocks
Rock hounding
Member since April 2020
Posts: 180
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Post by choochoorocks on May 6, 2024 23:16:30 GMT -5
Hello, So I went hiking recently and came across a few pieces of this jasper as float. They are jasper with tiny orbs. This was in the San Francisco Bay Area and not anywhere near Morgan Hill. As this was the third location in the Bay Area where I've found poppy jasper, I'm beginning to think they are actually relatively common. Perhaps experts can weigh in on if this is true. So here are the pieces showing how they look like. I tumbled them in stage 1 for a couple of weeks and unfortunately they didn't take too well to being tumbled. Here is the piece with the clearest/nicest looking poppies. It's about 2.5 inches long, with yellow-centered poppies bordered first by dark red, then lighter red:   Here is another piece. Its poppies appear to be a single color:  Under a microscope:  This next guy is interesting. I didn't realize it has orbs until I tumbled it. Its orbs are really not obvious.  The color on my microscope's screen got washed out in the below picture, but in person you can see that orbs have an outer pink circle, then a clear circle, then sometimes a yellow center (which is often missing).  On one edge of this piece the material becomes transparent (agate or quartz, I don't know), and the orbs here look much nicer: concentric outer rings of red, then pink, then red, then yellow. Unfortunately, this transparent edge is very small.  This last piece is mostly just a piece of what appears to be colorful mossy agate I found at the same location.   Showing an area with pretty green and pink moss. Unfortunately this piece was pretty fractured, made worse by tumbling.  But in one corner, there are a few very subtle orbs that are basically transparent. You can see the dark centers in the middle of clear circles below.  |
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jcooks
off to a rocking start
Member since December 2022
Posts: 22 
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Post by jcooks on May 7, 2024 15:52:28 GMT -5
Hey!
I'm not an expert but I'm pretty familiar with poppy jasper and it's formation. It's definitely not a "common" occurrence per se, but it does occur in many places in the Franciscan Complex here in CA. The conditions of deposition (in the way of chert), metamorphism/metasomatism by means of underwater basalt deposition and faulting, and then the eventual deposition on land of the Franciscan Complex in the coastal ranges happen to be the perfect conditions to form orbicular jaspers/metacherts. Those deposits are spread all over along the Coastal Ranges of CA, some in unexpected areas like in the Franciscan Melange.
The types you posted above are relatively common in these parts, probably one of the most prolific types of poppy jaspers found in CA. It's also identical to the poppy jaspers found in the Olympic peninsula of Washington. You could hold a specimen of each next to each other and never know they were from hundreds of miles apart. The Black Sea also has similar deposits.
Nice finds btw!
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jcooks
off to a rocking start
Member since December 2022
Posts: 22
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Post by jcooks on May 7, 2024 16:08:20 GMT -5
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choochoorocks
starting to spend too much on rocks
Rock hounding
Member since April 2020
Posts: 180
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Post by choochoorocks on May 9, 2024 15:35:10 GMT -5
Hey! I'm not an expert but I'm pretty familiar with poppy jasper and it's formation. It's definitely not a "common" occurrence per se, but it does occur in many places in the Franciscan Complex here in CA. The conditions of deposition (in the way of chert), metamorphism/metasomatism by means of underwater basalt deposition and faulting, and then the eventual deposition on land of the Franciscan Complex in the coastal ranges happen to be the perfect conditions to form orbicular jaspers/metacherts. Those deposits are spread all over along the Coastal Ranges of CA, some in unexpected areas like in the Franciscan Melange. The types you posted above are relatively common in these parts, probably one of the most prolific types of poppy jaspers found in CA. It's also identical to the poppy jaspers found in the Olympic peninsula of Washington. You could hold a specimen of each next to each other and never know they were from hundreds of miles apart. The Black Sea also has similar deposits. Nice finds btw! Cool info! Do you have pointers to material explaining Poppy jasper formation? |
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jcooks
off to a rocking start
Member since December 2022
Posts: 22
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Post by jcooks on May 9, 2024 18:49:41 GMT -5
Hey! I'm not an expert but I'm pretty familiar with poppy jasper and it's formation. It's definitely not a "common" occurrence per se, but it does occur in many places in the Franciscan Complex here in CA. The conditions of deposition (in the way of chert), metamorphism/metasomatism by means of underwater basalt deposition and faulting, and then the eventual deposition on land of the Franciscan Complex in the coastal ranges happen to be the perfect conditions to form orbicular jaspers/metacherts. Those deposits are spread all over along the Coastal Ranges of CA, some in unexpected areas like in the Franciscan Melange. The types you posted above are relatively common in these parts, probably one of the most prolific types of poppy jaspers found in CA. It's also identical to the poppy jaspers found in the Olympic peninsula of Washington. You could hold a specimen of each next to each other and never know they were from hundreds of miles apart. The Black Sea also has similar deposits. Nice finds btw! Cool info! Do you have pointers to material explaining Poppy jasper formation? Thanks! I don't have any real reference material, what little info is out there is a generalization someone made years ago stating that it's just feldspar or quartz crystals that form the "seed" of the crystal formation "in rhyolite." From my experience in finding veins of the material and studying geologic studies, this is rubbish. Other than actual orbicular rhyolite, I have never seen rhyolite anywhere near a poppy/orbicular jasper vein. What is ALWAYS found is a) chert, b) greenstone (metasomatized basalt), c) manganese & iron, and d) nearby serpentine and/or schistose rock. Shale is sometimes present too. It's more of a "jasperized metachert" than it is anything else. I believe it has something to do with underwater volcanoes where basalt intruded it's way through layers of chert and the resulting hydrothermal fluids metasomatized the chert. Afterwards, additional metamorphism occurred from the subduction of the Pacific oceanic crust under the North American plate, which is what formed the entire Franciscan complex Coastal Ranges, and brought these deposits to the surface along with the serpentinized ultramafics and everything else along with them. More hydrothermal fluids seeped through and additionally metamorphosed the jasper, folding, brecciating, and rehealing it with silica rich fluids. That's why it's highly fractured with relatively small chunks of solid material. It's just my theory, but I'm not the only one that's came up with that exact one. I could be wrong though, it wouldn't be the first time! |
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Sabre52
Cave Dweller 
Me and my gal, Rosie
Member since August 2005
Posts: 20,494
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Post by Sabre52 on May 20, 2024 14:37:29 GMT -5
One of my gem books says the Golden Gate bridge actually has poppy jasper under some of it's supports and there are known sites in back of the old Sutros baths and in gravels clear up the coast to Washington in the Franciscan Formation. Very similar material also occurs in Hunters Valley in the MT Willliams range west of the Sierras. Jcooks poppy origin explanation is very similar to what I was told too.
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choochoorocks
starting to spend too much on rocks
Rock hounding
Member since April 2020
Posts: 180
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Post by choochoorocks on Aug 30, 2024 17:51:58 GMT -5
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demihuman
starting to spend too much on rocks
Member since May 2024
Posts: 131
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Post by demihuman on Aug 31, 2024 9:45:50 GMT -5
Super cool! I have been doing a lot of collecting around San Jose, Morgan Hill and Gilroy but I haven’t found any classic poppy jasper yet. I have found some spotted stuff. There is a lot different colors though, even at the same spots the variety is pretty striking. You have some great rocks there!
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choochoorocks
starting to spend too much on rocks
Rock hounding
Member since April 2020
Posts: 180
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Post by choochoorocks on Sept 2, 2024 20:34:54 GMT -5
Super cool! I have been doing a lot of collecting around San Jose, Morgan Hill and Gilroy but I haven’t found any classic poppy jasper yet. I have found some spotted stuff. There is a lot different colors though, even at the same spots the variety is pretty striking. You have some great rocks there! I'd be interested to see pictures of your finds! |
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demihuman
starting to spend too much on rocks
Member since May 2024
Posts: 131
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Post by demihuman on Sept 4, 2024 22:28:26 GMT -5
Check this one out:  |
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hplcman
spending too much on rocks
Looking forward to my Friday Night Barrel Clean out!
Member since August 2022
Posts: 492
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Post by hplcman on Sept 5, 2024 10:14:03 GMT -5
Super cool! I have been doing a lot of collecting around San Jose, Morgan Hill and Gilroy but I haven’t found any classic poppy jasper yet. I have found some spotted stuff. There is a lot different colors though, even at the same spots the variety is pretty striking. You have some great rocks there! I'm up in Petaluma and have found some interesting rock formations out at the beach, but nothing with orbs (yet). Goat Rock Beach is a great place to hound, but the rock can be pretty heavily fractured sometimes... I'll post some pictures.     |
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demihuman
starting to spend too much on rocks
Member since May 2024
Posts: 131
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Post by demihuman on Sept 5, 2024 13:38:45 GMT -5
Cute dog! Man I love green rocks! Do you ever go up to the Russian River? I hear there are some good rocks around there. I know there are a lot of gravel bars to explore.
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hplcman
spending too much on rocks
Looking forward to my Friday Night Barrel Clean out!
Member since August 2022
Posts: 492
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Post by hplcman on Sept 5, 2024 15:30:32 GMT -5
Cute dog! Man I love green rocks! Do you ever go up to the Russian River? I hear there are some good rocks around there. I know there are a lot of gravel bars to explore. Thanks! It's a dog friendly beach and it's his happy place, so I try to get him out there as often as I can!! Shades of green seem to be pretty common out there, if you're ever up this way you should check it out! The Russian River is great, LOTS of gravel bars and stuff. I have found a few nice rocks out there. But it's sort of like those pictures of that dried up lake you posted a while ago. All of the rocks are covered with a layer of white weathering that makes it a bit harder to figure out what's underneath. At least for me... I haven't developed the skill of x-ray vision that some members on here seem to have!  |
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demihuman
starting to spend too much on rocks
Member since May 2024
Posts: 131
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Post by demihuman on Sept 5, 2024 16:11:14 GMT -5
Just have to wait until it rains or bring a squirt bottle : ) Some of that pond scum is pretty gnarly though. I guess you could bring a hammer, but I don't love smashing rocks a part just to see what's on the inside, especially if I am not at a sanctioned rock collecting spot or BLM or something. |
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Post by rockjunquie on Sept 5, 2024 23:12:59 GMT -5
Super cool! I have been doing a lot of collecting around San Jose, Morgan Hill and Gilroy but I haven’t found any classic poppy jasper yet. I have found some spotted stuff. There is a lot different colors though, even at the same spots the variety is pretty striking. You have some great rocks there! I'm up in Petaluma and have found some interesting rock formations out at the beach, but nothing with orbs (yet). Goat Rock Beach is a great place to hound, but the rock can be pretty heavily fractured sometimes... I'll post some pictures. The rocks are cool, but your rock pup is adorable! |
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lapidary1234
spending too much on rocks
"If you like rocks you can't be all bad!!" ~ old timer quote
Member since October 2021
Posts: 293
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Post by lapidary1234 on Sept 14, 2024 21:43:25 GMT -5
Nice stones and pictures. Poppy jasper is a stone I don't have much of (if any).
Can I ask a question about your microscope? What type/brand/model is it? Magnification rates? Do you have to cut slabs and make a kind of "slide" for it? Finally (and most importantly) does it have the digital camera built in?
I am really wanting to get a microscope with a digital camera built in! I have seen a cheap looking handheld model but the reviews say that the rechargeable lithium ion battery is super cheap and will only last a few months.
If you could provide specs of what you use or if anyone knows of something like this please please please lemme know!!
I recently got a 30&60× loupe with built in led and it is super cool! Well worth the $12 or so that it cost. If it had a built in camera I'd be set!!
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choochoorocks
starting to spend too much on rocks
Rock hounding
Member since April 2020
Posts: 180
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Post by choochoorocks on Sept 24, 2024 10:28:08 GMT -5
Hi, I have a cheapo digital microscope that I got on Amazon. Its brand is Dcorn. It has a 7" screen. When I look at things on the screen, they look to be several times magnified, maybe roughly 10x. The magnification can't be adjusted. Objects don't need to be flat to be viewed so long as they fit under the tube.
It can take pictures and shoot videos to be stored on an SD card, but the controls are finicky and I can never figure how to activate one mode vs the other reliably. The battery lasts several hours, which is great.
Hope this helps!
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