scaboorocks
starting to shine!
Member since May 2021
Posts: 34
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Post by scaboorocks on Sept 12, 2021 7:18:29 GMT -5
Maybe chert or Jasper? Either way this is representative of a lot the rocks we find. Sometimes the blue wears away in the tumbler to leave the brown/orange color. Sometimes vice versa. I'm still learning how you photograph macro on my phone. I may have been a bit to close
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scaboorocks
starting to shine!
Member since May 2021
Posts: 34
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Post by scaboorocks on Sept 12, 2021 10:18:17 GMT -5
I was able to get a couple of better photos in the sun
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scaboorocks
starting to shine!
Member since May 2021
Posts: 34
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Post by scaboorocks on Sept 12, 2021 10:21:48 GMT -5
This were collected from the same beach and came from the same batch. Maybe an agate? I'm horrible at classifying. Lol
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Post by greig on Sept 12, 2021 10:26:13 GMT -5
Nicely done. My vote on an ID from the pic would be chert.
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scaboorocks
starting to shine!
Member since May 2021
Posts: 34
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Post by scaboorocks on Sept 12, 2021 11:04:42 GMT -5
Nicely done. My vote on an ID from the pic would be chert. I'm leaning that way as well. Honestly don't know why. I'm not sure I know the difference between chert and Jasper.
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Post by greig on Sept 14, 2021 12:01:02 GMT -5
Nicely done. My vote on an ID from the pic would be chert. I'm leaning that way as well. Honestly don't know why. I'm not sure I know the difference between chert and Jasper. Flint, chert, and jasper are common names of opaque microcrystalline quartz of various designs/colours. It is not inaccurate to use one over the other for the same sample.
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scaboorocks
starting to shine!
Member since May 2021
Posts: 34
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Post by scaboorocks on Sept 14, 2021 12:05:45 GMT -5
I'm leaning that way as well. Honestly don't know why. I'm not sure I know the difference between chert and Jasper. Flint, chert, and jasper are common names of opaque microcrystalline quartz of various designs/colours. It is not inaccurate to use one over the other for the same sample. Interesting. What made you say chert over Jasper then?
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Post by Peruano on Sept 14, 2021 16:55:53 GMT -5
Perhaps without good reason we tend to expect jaspers to have colors (often reds and browns) produced by contaminants in the silca oxide matrix. Cherts tend to be greyish and less brightly colors. Off the top of my head, I always envision cherts to be formed under water whereas agates and jaspers may form in cavities often far below the surface. But I'm reaching to make those hard rules. Some of the more refined distinctions may be read in www.quartzpage.de/ an invaluable source of photos, definitions and terminology for all of the quartz/chalcedony relatives.
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Post by stephan on Sept 14, 2021 17:37:04 GMT -5
It gets way more wonky than that. Sometimes chert becomes jasper. A good example of this is Stone Canyon jasper, which begins its life as radiolarian chert, formed, as Peruano suggests, at the bottom of the ocean. It typically (here in California) is yellowish, brown or brick red. Through tectonic action, it is crushed and moves around, eventually ending up on the North American plate. There, exposed to hydrothermal action with high-silica water, the pieces of chert are healed by the formation of agate or chalcedony. This same silica-water (sometimes) also seeps into the pores of the chert and jasperizes it.
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