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Uncle Siphuncle

To prep or not to prep

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Uncle Siphuncle

I found this ammonite recently in hard, microcrystalline Eagle Ford flagstone.  Guessing it is Acanthoceras +/-, preserved as a calcite steinkern.  I’m not sure how readily the matrix would release from the fossil, but I’m guessing it is not too eager.  If anyone has experience prepping this hard stuff, I’m open to suggestions.  Otherwise I’ll just cut the rock down to a small tile and leave the fossil as-is.  @Ptychodus04

1F27C874-C083-4920-A08B-B9A0041DD54B.jpeg

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Ptychodus04

@Uncle Siphuncle That looks like quite a project. If you have a very small scribe (Aro or Micro Jack sized) you could work the matrix off under a microscope. My experience has been that most of the time the matrix tends to come cleanly off calcite steinkerns but you really need to have good magnification to safely get close enough with the scribe.

 

Then again, it could be sticky and all my thoughts fly right out the window. :wacko:

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Uncle Siphuncle

Thanks Kris.  Often these slabs have mutliples.  I’ll wash the slab and if there is a less complete specimen, I’ll experiment with it first.  

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RJB

  If the matrix does come off with not much trouble i would attack one of your multi's.  That would be cool.  Good luck

 

RB

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Uncle Siphuncle
4 hours ago, RJB said:

  If the matrix does come off with not much trouble i would attack one of your multi's.  That would be cool.  Good luck

 

RB

I have a feeling it will be sticky, tenacious stuff, not unlike sandstone sometimes found bonded to Cenozoic sand dollars.  

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Ptychodus04
2 hours ago, Uncle Siphuncle said:

I have a feeling it will be sticky, tenacious stuff, not unlike sandstone sometimes found bonded to Cenozoic sand dollars.  

The comparatively rough texture of an echinoid test allows for a happy and strong bond. The relatively smooth texture of an ammonite shell has the opposite effect. I've gotten wonderful results from some nasty matrices on ammonites. It is even better when there's no actual shell material preserved to deal with.

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Uncle Siphuncle
1 hour ago, Ptychodus04 said:

The comparatively rough texture of an echinoid test allows for a happy and strong bond. The relatively smooth texture of an ammonite shell has the opposite effect. I've gotten wonderful results from some nasty matrices on ammonites. It is even better when there's no actual shell material preserved to deal with.

I hope for the same here!  Thx

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Ludwigia

I'll go along with the advice the others are giving you. Good luck to ya.

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Uncle Siphuncle

I followed my instincts on this unsexy specimen since I figured I’d make a mess with the scribe in this hard, grainy limestone. Tiled with a diamond bladed angle grinder then one hard whack on edge with a 3 inch wide chisel and hand sledge.  Done.

49D42C6A-4118-403D-B1FF-50A561237107.jpeg

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Uncle Siphuncle

Whacked. @Ptychodus04

7E9FCE75-1BC5-4CAE-B449-A12DA6E1B6BF.jpeg

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Fossildude19

Nice! 

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Ptychodus04

@Uncle Siphuncle I still think it could be scribed nicely given the right combination of tools, magnification, time, and ability. :D 

 

Next time you find one in similar matrix, hold it back for me and I’ll see what I can do with it. I enjoy a challenge.

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Uncle Siphuncle
9 minutes ago, Ptychodus04 said:

@Uncle Siphuncle I still think it could be scribed nicely given the right combination of tools, magnification, time, and ability. :D 

 

Next time you find one in similar matrix, hold it back for me and I’ll see what I can do with it. I enjoy a challenge.

I'll give you one when I run through the middle Eagle Ford flags again.  On the split, it became clear that I wouldn't be rewarded with smooth, killer calcite preservation.  Instead, I got sort of a crusty limonite-like interface.  Not all Kef is created equal.  I'd much rather spend my time in the Arcadia Park.

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Ptychodus04
11 minutes ago, Uncle Siphuncle said:

I'll give you one when I run through the middle Eagle Ford flags again.  On the split, it became clear that I wouldn't be rewarded with smooth, killer calcite preservation.  Instead, I got sort of a crusty limonite-like interface.  Not all Kef is created equal.  I'd much rather spend my time in the Arcadia Park.

I agree. I much prefer the lower Britton to the others in the Kef.

 

Middle to Upper Britton is my fav for ammonites.

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Uncle Siphuncle
31 minutes ago, Ptychodus04 said:

I agree. I much prefer the lower Britton to the others in the Kef.

 

Middle to Upper Britton is my fav for ammonites.

One can never have too many Polyphtychodon teeth, mesays.

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