Fossilfinder49er Posted August 23 Share Posted August 23 This specimen appears to be an opalised/ fossilized marine invertebrate found in Washington state. The fossil is difficult to measure, but quite small (approx 3-5mm) in what I believe to be a type of crystal opal. The left eyeball appears very close to the surface and appears fully intact at certain angles, and distorted in others, resembling crystallisation. The entire specimen is a little over 3grams. Could anyone suggest the best place, preferably on the US West coast, to take this for further study? Having difficulty proving that these are not man-made. Cheers! Scott R Link to post Share on other sites
Misha Posted August 23 Share Posted August 23 I think you have a piece of slag glass,.or something similar. Certainly not a eurypterid, sorry 1 6 Link to post Share on other sites
Mahnmut Posted August 23 Share Posted August 23 Hi and welcome to the forum. Sorry to agree with Misha. There are two little spheres nicely placed like eyes on the sides of that dark inclusion. But there are more spheres visible that have no connection to the dark thing at all, hard to tell with the magnified images, but I´d guess they are gas bubbles. Best Regards, J 2 3 Link to post Share on other sites
Ludwigia Posted August 23 Share Posted August 23 On 8/23/2023 at 6:48 AM, Fossilfinder49er said: Could anyone suggest the best place, preferably on the US West coast, to take this for further study? I would agree with my colleagues, but if you really want to know for sure, then just take it to your nearest natural history museum or university geology department and show it to a resident geologist, mineralogist or paleontologist. 1 2 Link to post Share on other sites
digit Posted August 23 Share Posted August 23 "Crystal opal" refers to any opal that is transparent or semi-translucent. Other than non-gem-grade "common opal" or "potch" that is milky white without the iridescent colors that opal is famous for, I've never seen opal that didn't have a play of color within it. Natural quartz crystals tend to be white or a range of colors depending on the minerals occurring within the crystal lattice--smoky quartz, pink quartz, etc. The aqua color displayed by your item is very consistent with man-made glass which is due to a small amount of iron content in the raw sand used to produce it. The conchoidal fractures on the surface of your item, the dark inclusions, and the overall look is extremely consistent with a piece of slag produced during the manufacture of glass. 6 hours ago, Fossilfinder49er said: Having difficulty proving that these are not man-made. I can believe this as all indications point to this being debris from the manufacturing process. If you still believe you have a rare and highly unusual fossils (I can think of no physical or geological process which could entrap any fossil material within a surrounding of opal), then I think the advice of seeking a natural history museum in your area and contacting a geologist there to show images of your find. Cheers. -Ken 3 1 Link to post Share on other sites
ynot Posted August 23 Share Posted August 23 2 hours ago, digit said: Other than non-gem-grade "common opal" or "potch" that is milky white without the iridescent colors that opal is famous for, I've never seen opal that didn't have a play of color within it. Common opal can be any color and is found in many geologic environments. The majority of opal has no "play of color". I agree that the OP's piece is slag. 4 1 Link to post Share on other sites
Mark Kmiecik Posted August 23 Share Posted August 23 Anthropogenic leaverite. 1 Link to post Share on other sites
Fossilfinder49er Posted August 24 Author Share Posted August 24 From what I've heard there are two indications that it MIGHT BE glass, and no indication why anyone says it's man-made. I have several in near gem quality, which are natural rocks with this similar colored 'glass in it. I had scanning electron microscopy done which indicated that it's likely natural. Is there any way to prove a rock is a natural rock and not man-made? These pics are of the same color and texture as the others. It's a rock. I get the same response when I post pics of what is obviously an opal, so I guess pics aren't the best way to go about this, but here are some that in no way look synthetic. Link to post Share on other sites
Misha Posted August 25 Share Posted August 25 The two other objects you added here now look like quartz Pebbles, not sure what the last picture shows. I don't see what relevance SEM imagining would have here as that would in no way demonstrate if something is manmade or not. Link to post Share on other sites
Fossilfinder49er Posted August 25 Author Share Posted August 25 If it was quartz then it's more like a geode with the same color, and textured 'glassy' material in the middle as the one with the fossil which I can clearly make out an eyeball in. Quartz cannot have this type of 'inclusion', while opal can. Opal can also be transparent and have 'bubbles'. Is there a test which conclusively proves a rock is natural vs synthetic? Link to post Share on other sites
ynot Posted August 25 Share Posted August 25 It is not possible to say what the new pictures are as there is no information about them.... hardness streak color location fracture and pictures of all sides. 1 hour ago, Fossilfinder49er said: Quartz cannot have this type of 'inclusion', while opal can. Neither can or will have this type of inclusion, ever. 1 hour ago, Fossilfinder49er said: Opal can also be transparent and have 'bubbles'. Opal can be transparent but will never have "bubbles" although on very rare occasions it can have a small void in the center of a nodule partially filled with water (often called level quartz). The multiple bubbles, folding and bits of carbon (black inclusions) and crazing of the original piece leave no doubt it is a piece of glass that was melted in a fire. whether a camp, house, forest or kiln fire we may never know, but certainly melted glass! 5 Link to post Share on other sites
digit Posted August 25 Share Posted August 25 Thanks, Tony! I appreciate that we can turn to your experience on questions of a mineral nature. Cheers. -Ken 1 Link to post Share on other sites
Ludwigia Posted August 25 Share Posted August 25 8 hours ago, Fossilfinder49er said: Is there any way to prove a rock is a natural rock and not man-made? I already suggested you show it to a geologist or mineralogist. They have their methods. 1 Link to post Share on other sites
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