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  • Todd83 posted an image in the group Group logo of What is it?What is it? from the myFOSSIL app 4 months, 1 week ago

    4 months, 1 week ago
    4 months, 1 week ago

    The top pic is a geodized Crinoid that sold online. The bottom pic is my specimen. I was told my specimen is just a geode, not a geodized crinoid. Can anyone help me to understand the differences? Somewhat new to this, appreciate any help. Thanks!

    • I’m quite new to but I don’t see much of a difference

    • I did clean mine thoroughly which is why there is a difference in color but other than that I can’t see much of a difference either. Appreciate the response

    • It’s hard to tell, yours is worn so that it could be either an eroded crinoid or a lump of rock that resembles a worn crinoid. Mabey @daniel-park will be able to tell, there is another post with multiple angles of this.

    • Makes sense, I appreciate the response a-trilobite

    • Crinoids are echinoids, which have radial symmetry. A starfish is a good example and you can split it into 5 identical sections which illustrate radial symmetry. If you look at your specimen from the end, radial symmetry would strongly suggest it to be a fossil and not just a rock. That is why pictures from different angles are useful. The picture you have is from the side which would not show any radial symmetry, if it exists. However, from your picture, there is nothing to suggest any symmetry.

    • Thanks for the information Patrick. My original post from yesterday has pictures from different angles. Would you mind taking a look and letting me know what you think? Thanks!

    • I don’t see any features that would suggest a biological origin.

    • Honestly I’m not sure either. For now I’m going to go with a very crinoid-like rock.

    • Thanks Daniel Park, appreciate the reply. I just posted another picture pointing out what I am seeing that may or may not help with the specimen identification if you have a second to take a look? Thanks again

    • I have never heard of geodize crinoid and that statement does not make sense to me. A geode is when an empty space fills with mineral rich water and precipitation occurs leaving behind the minerals (can be any mineral but typical ‘geodes’ are quartz). Animals can become geodes during fossilization, a good example is a shell with be buried and the organism inside will rot out leaving behind an empty space inside of the shell. HOWEVER! Crinoids don’t look like that so it is not a crinoid that has a geode inside. There are no internal or external structure of a crinoid visible. Maybe the person meant that it is a crinoid that has been turned into a nodule for some reason (is encased in a ‘geode’). The only way to tell is to saw your rock in half and see if there is a crinoid inside. You’re rock looks to me more like it has a line of symmetry that the crystals made during their growth.

    • Hi Chloe, thanks for the information. Check out this link if it works and scroll down to “Theory 2” if you have a minute. I’m kind of new to this and probably didn’t madeThanks again for your reply http://www.amfed.org/editor/BEAC/Articles/2011/AdultArticlesAdv/2.Geodes%20in%20Sedimentary%20Rock.doc

    • Didn’t mean to hit send yet lol… anyway I was just saying I probably made things confusing due to my lack of knowledge so my apologies. Doesn’t look like the link sent correctly either, might try to google the link information and see if it works if your interested in reading it. Thanks!