Cleaning a fish fossil plate

[Vleuver]

Hey all,

 

I've got a beautiful plate from Green River containing two Priscaceras. The stone itself however is kind of ugly, and I'd like to at least egalize the colours of the stone if possible.

 

Would that be possible, and how could I do that? How about slightly scuffing the stone itself?

 

 

[Thecosmilia Trichitoma]

I personally would keep the plate as is, but @RJB and @Ptychodus04 have worked on lots of GRF plates and might be able to tell you how to proceed.

[Vleuver]

Thank you for your reply.

 

I'm pretty sure that the colours have been caused by the piece being in someone's living room for over 20 years. The discoloration on the left bottom side is caused by me trying to clean it with water and a tiny bit of soap and a soft cloth.

[Fossildude19]

Mild air abrasion with sodium bicarbonate would probably clean this nicely. 

[snolly50]

I hope I look that good when I'm 50 million years old! I think the discoloration adds to the presentation; but if you want it immaculate - as Tim suggested, air abrade it. Mask off the fish and have at it. If you wish a low tech approach you could scour the surface with sandpaper. What you are after is the unsullied surface just beneath the present one. Unfortunately, I think any approach will yield an unnaturally smooth surface, devoid of texture.

[digit]

I'm not so sure that is (recent) soiling and discoloring. This appears to be a nice dual-fish plate from the famous 18" layer which often preserves fishes much nicer than the split-fish layer. If you do some internet image searches for "green river formation 18 in layer" you'll see many examples of a more grayish background as opposed to the more pale tan oil shale of the split-fish layer.

 

 

Cheers.

 

-Ken

[Ptychodus04]

I would do nothing to it. This looks like normal variation in coloration present in the 18” layer.

 

The 18” Layer contains microscopic layers of matrix which alternate between light and dark. The scrub with soap and water simply removed one micr-layer (lighter) and exposed the layer below (darker). Anything you do will likely result in an unsatisfactory result. It is very hard to safely remove rock near the fish, so the piece will take on an unnatural appearance (as noted by @snolly50 above).

[jpc]

36 minutes ago, Ptychodus04 said:

I would do nothing to it. This looks like normal variation in coloration present in the 18” layer.

 

The 18” Layer contains microscopic layers of matrix which alternate between light and dark. The scrub with soap and water simply removed one micr-layer (lighter) and exposed the layer below (darker). Anything you do will likely result in an unsatisfactory result. It is very hard to safely remove rock near the fish, so the piece will take on an unnatural appearance (as noted by @snolly50 above).

I agree 100%.  It looks great as is.  That is the natural rock you are seeing.

 

[RJB]

  You could put it in the 'Rock Equalizer 2000' for 24 hours and WA  LAAAA!!!  But seriously, what Ptychodus said is the best idea.   Maybe frame it and hang it on a wall?  Good luck

 

RB

[Randyw]

If it was mine I’d leave it as is. It adds some character to the piece. Nice specimens by the way!