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Post by Peruano on Feb 13, 2022 17:37:23 GMT -5
A couple of folks have asked to see what I'm finding on the beach and I've struggled with a non synched cell phone camera, and a wimpy point and shoot (hey leave the good stuff away from the sand and the salt), I've come up with a few examples some quite blurred.. My apologies. A m ushroom rhyolite. A large piece of rhyolite which could not decide on its preferred color. There are lots of small to medium chalcedony nodules, some very tumbled and some quite rough in texture. Of interest are some that border on carnelian orange. Some of the white and carmel rounded specimens are actually very heavy remnants of large conchs that after a few decades, centuries, or thousands of years turn into incipient cabs. Its all fun and today I found larger and more colorful chalcedony up on fossil beaches, not influenced by the tides and worth a trip back to the site.
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Post by jasoninsd on Feb 13, 2022 18:24:04 GMT -5
Those look like some really fun beach finds Tom!
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Post by rockjunquie on Feb 13, 2022 19:21:58 GMT -5
Thank you for the update. Looks like you have a good haul!
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Post by fernwood on Feb 14, 2022 6:20:14 GMT -5
Nice finds. The lower one in the first close up is really cool.
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Post by Peruano on Feb 21, 2022 17:27:47 GMT -5
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Post by Son Of Beach on Feb 21, 2022 17:32:20 GMT -5
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Post by jasoninsd on Feb 21, 2022 17:50:03 GMT -5
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vwfence
has rocks in the head
Member since January 2013
Posts: 557
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Post by vwfence on Feb 22, 2022 16:07:30 GMT -5
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vwfence
has rocks in the head
Member since January 2013
Posts: 557
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Post by vwfence on Feb 22, 2022 16:08:20 GMT -5
well i messed that up . is the picture Rhyolite and chalcedony
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Post by Peruano on Feb 22, 2022 21:49:47 GMT -5
The photo you highlighted is a rhyolite. All of the chalcedony are white, beige, or light orangish. In many of the stones the rhyolite seems to have spaces, or be brecciated and subsequently invaded by the chalcedony. I wonder if this is a special situation in deep marine substrates. There is also a fuzzy, not quite ready to take a shine white inclusion on some of the chalcedony that reminds me of choco agate material. Perhaps someone with more geology background will id it for us.
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vwfence
has rocks in the head
Member since January 2013
Posts: 557
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Post by vwfence on Feb 22, 2022 22:52:22 GMT -5
the area around my house is full of rhyolite like that with chalcedony in it as well as pink and gray banded or spotted
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Post by Peruano on Feb 23, 2022 9:11:06 GMT -5
I've forgotten where you are located, but suspect its AZ. By definition rhyolites have lots of silica and in my simplistic view of geological processes, silicates in solution peculate through spaces and precipitate out as opals and chalcedony relatives. Probably enhances as solutions move through silica rich substrates like rhyolitic fields. Filling spaces creates wonderful shapes, twists, and layers. Have I offended anyone's technical knowledge?
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vwfence
has rocks in the head
Member since January 2013
Posts: 557
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Post by vwfence on Feb 23, 2022 11:59:23 GMT -5
yes , im in north west Arizona at the base of the Black mountains and just west of the Cerbats
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