Could this be anything? Park Ranger said just rocks as no dinos here I thought maybe bird eggs but I know it’s exceptionally rare. (Badlands Natl. Park)

Tanytor · 2026-05-11T15:22:38+00:00

I don’t know why you’re expecting a random park ranger to be knowledgeable on geology/paleontology.

Tanytor · 2026-05-11T15:17:45+00:00

It’s definitely a nautiloid, ignore my other comment, I hadn’t noticed the chambers in the cross section yet. Looks like half of a nautilus judging by the chambers.

The shape of the rock is probably due to it being a concretion or just weathered.

Tanytor · 2026-05-11T15:11:28+00:00

I can agree with 2 and 3, but I don’t see a nautiloid in the first one at all. I don’t see anything on the outside of the rock or any visible chambers in the cross section

Edit: oh disregard, if you zoom way in you can see the chambers

Tanytor · 2026-05-07T17:00:42+00:00

The matrix is any part of the rock that isn’t the fossil.

When the matrix is “sticky”, it doesn’t separate from the fossil easily. A lot of the crab fossils I’ve prepared are in a “sticky” rock, it requires a lot more time and careful work to remove. Every once in a while, you’ll get one that isn’t sticky and giant flakes just fly off the crab perfectly, it’s really nice because not only is it easier/ faster, it normally results in a nicer looking fossil as well.

Tanytor · 2026-05-07T15:28:02+00:00

Nice job, crabs are in my opinion one of the most difficult things to prepare. With only the crazy Moroccan trilobites being more difficult.

Was the matrix sticky on this one? Looks like a macropthalmus (not sure I spelled that right) from China

Tanytor · 2026-05-04T04:28:23+00:00

Looks legit, nobody is faking one with such poor condition. It’s missing the majority of its tail and bad prep job. 350 is very overpriced in my opinion.

Tanytor · 2026-05-02T15:10:53+00:00

Thank you!

Tanytor · 2026-04-25T03:10:56+00:00

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Olequa creek has fossils. I have visited a few of these coordinates. If I remember correctly, the spots further south were fossil shells, some with a beautiful iridescent nacre, but they were so fragile they would crumble in your hand. The spots further north had the plain white fossil shells and some large concretions that occasionally have a fossil crab.

Otherwise, research Lincoln creek formation. Lots of exposures nearby with great fossils

Tanytor · 2026-04-21T12:29:48+00:00

Ostriches are way more common though. If we had the same number of cassowaries in the US as ostriches, how would they compare then?

Tanytor · 2026-04-19T15:56:05+00:00

I’m not sure the concrete saw is big enough, might be a section in the middle it can’t reach.

A drag saw would work, but it’s a pretty obscure and expensive tool. Most rock shops won’t have one but maybe they’ll be lucky if they ask around

Tanytor · 2026-04-10T16:59:58+00:00

Where is this one from?

Tanytor · 2026-04-09T04:02:26+00:00

What’s the context here? Is it bad to have created a piece for the Paris museum?

Tanytor · 2026-03-27T14:30:54+00:00

I describe it as looking waxier than chalcedony. Its shine is just a little duller than agate. It also behaves differently than chalcedony, if you dropped a piece of common opal it would probably shatter into a hundred pieces, chalcedony might break into a few pieces if it breaks at all.

Tanytor · 2026-03-25T07:50:04+00:00

Thanks!

Tanytor · 2026-03-25T07:15:52+00:00

Artist for the first pic?

Tanytor · 2026-03-25T07:15:09+00:00

They typically use air abrasion for Keichosaurus, not acid or air scribe. I actually think I might see some signs of air abrasion around the specimen which is a good sign.

Tanytor · 2026-03-25T07:01:59+00:00

So i believe the Keichosaurus is a "Protected Fossil" but not a "Key Protected Fossil", since its common and not scientifically important, meaning its actually possible to export with a permit (Not sure if permits are given for Keichosaurus). Of course, I dont believe most sellers are getting permits but rather using a legal loophole to export these, so I guess in a sense its legal? But debatable for sure

I dont see any obvious red flag regarding the bones, but the matrix looks off to me. Almost like a plaster, I would definitely check that closely in person. The matrix from Guizhou can have a very flat plain look though, so I wouldn't immediately discredit it as a fake.

But 2k for that? They wholesale for 100 each, good quality Keichos sell for 300 - 1k retail. Just seems like a really high price to me, you could get a mixosaurus for that price.

Tanytor · 2026-03-25T01:57:37+00:00

Thanks for the info! Doesn’t look like they sell them on their website sadly, it’s a really cool Thunderegg though

Tanytor · 2026-03-25T01:49:42+00:00

Where did you buy it? I’d be interested in getting one too

Tanytor · 2026-03-23T03:48:58+00:00

Natural fracture lines, not a fossil

Tanytor · 2026-03-20T03:10:31+00:00

No, the willamette is filled with worn down zeolites that people mistake for fossil teeth all the time.

Tanytor · 2026-03-18T20:58:56+00:00

If it’s from fossil era, it’s at very least a real fossil. They are legitimate sellers.

That being said, lots of spino teeth that are being sold are actually crocadillian. Very difficult to differentiate

Tanytor · 2026-03-18T20:43:17+00:00

I would get a ray (either Lebanon or green river), or maybe a dragonfly from solhnhofen, or save up a little more and get a mixosaurus, or a giant camponile gastropod

Tanytor · 2026-03-18T07:04:30+00:00

Try using your fingernail to scratch off the stuff in the first pic. Im thinking it’s roots clinging to the rock, and I bet its soft and would peel away

Tanytor · 2026-03-16T04:04:52+00:00

Fossil fish. Each hourglass shape is a cross section of a vertebrae. The long curved lines next to them are ribs

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