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winnph

Beach agate, possible bivalve?

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winnph

I found this on a rocky beach in West Seattle. Looks to be pretty transparent with a bit of banding. I assume it's just geological, but based on the size and shape I guess it could maybe be a bivalve fossil? SG is 2.61

IMG_20190326_145626.jpg

IMG_20190326_145646.jpg

IMG_20190326_145526.jpg

IMG_20190326_145507.jpg

Edited by winnph

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ClearLake

I'm not seeing a fossil in this one.  I think your first instinct was correct, a nice piece of quartz.

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Tidgy's Dad

Very pretty indeed! i'd have it. :)

But not a fossil, i'm afraid. 

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winnph

Yeah I didn't think so, just thought I'd throw it out there... Thanks!

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abyssunder

The first two pictures remind me of percussion marks on the surface of a tumbled silica rich pebble.
Don't forget the barnacle attachment scars as a possibility for the other strange patterns. :)

 

5c9ac9804fb0b_Figure2.thumb.jpg.008a5d7d766657c3d0dcbc2571e00ed5.jpg

 

barnacle scars

Edited by abyssunder

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winnph

Yep, the markings are definitely percussion marks and recent barnacle remnants, the only reason I thought it could possibly be a clam cast/mold is based on the banding it is clearly an agate that filled a void in the sandstone, and it has a similar overall shape and size, kind of a flattened ovoid, but it doesn't really look THAT much like one. I'm already convinced it isn't!

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Steve

Your rock is called carnelian a type of quartz but not a true agate.I have tumble polished lots of them they are great for this and look great....,.....Steve

004.JPG

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Steve

048 (Large).JPG

050 (Large).JPG

027 (Large).JPG

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winnph

Those look very nice! I am not positive that's what mine is, though, as there appears to be concentric banding that looks more like a typical agate. I took this photo yesterday before putting it in the tumbler this morning, you can kinda see the concentric banding centered near my top finger. I'll post a photo after the rough tumbling is done in a week or two, maybe we'll be able to see into it a little more clearly.

IMG_20190326_145642.jpg

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ynot
3 hours ago, winnph said:

! I am not positive that's what mine is, though, as there appears to be concentric banding that looks more like a typical agate.

Carnelian is a form of agate and can be "banded" like other agates.

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winnph

Got it! I was assuming (as is always unwise) that it would have the more "fractured" appearance of the specimens shared

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winnph

Just thought I'd share what it looks like after rough tumbling.

IMG_20190404_183949.jpg

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