Advice on removing sandstone from a hell creek fossil

[Spitfirejhc]

Hello. I am a novice collector and have so far only used a combination of manual cleaning, water/toothbrush, and acetone to remove the sandstone matrix around the back of a dinosaur bone (ischium). I collected it last year as part of a trip to private land in the hell creek formation.

 

I have read that most acids won’t work well on sandstone, although there are some articles recommending DMSO.

https://www.researchgate.net/publication/250070644_An_easy_way_to_remove_fossils_from_sandstones_DMSO_disaggregation#:~:text=Many sandstones (89 of 127,is simple and relatively inexpensive.
 

However I didn’t see many folks supporting this articles claim.

 

Maybe I just need to keep at it with the brush, but it is very slow going and I worry about damaging the underlying fossil. I have not soaked it in anything yet, only run it under the tap.

 

I’d appreciate advice from anyone who has experience dealing with sandstone removal like this. Maybe I just need to try soaking it overnight and then brushing again.

 

I’m also not certain what dinosaur species (probably hadrosaur, maybe Edmontosaurus then). Fairly sure it is part of an Ischium.

 

thank you for your time.

Edited June 1 by Spitfirejhc

[hadrosauridae]

thats not "sand stone" in the strict sense.  The matrix of the Hell creek comes off of fossils fairly easy.  What it looks like, is that your specimen has ironstone concretion binding with both the sandstone and the fossil.  It can be very troublesome to remove without proper power tools, and even then it should be under a microscope because you can quickly begin remove bone surface if you cant see the contact spot in sharp detail.

 

Dont try to use acid, your fossil wont survive.  If its not very well consolidated, id be very hesitant to be scrubbing on it at all.

[Spitfirejhc]

Okay thanks for the guidance. It is well consolidated so scrubbing with just water has been fine.

 

When I pick at this dirt on the back area it does crumble into fine powder quite quickly. Would ironstone do that? As you likely can see, I am probably losing loose pieces of fossil at the same time though.

 

I had also wondered if I had just managed to overglue it as part of the extraction process. 

 

Here is what it looks like after a small chip at it.

 

I wonder if it’s just time to seal with Paraloid and move on.

Edited June 2 by Spitfirejhc