Muramotoceras ammonite resto?

[Mochaccino]

Hello,

 

I came across this Muramotoceras ezoenze (yezoense?) ammonite from Yubari, Japan, and was wondering if it seems legit and natural without restoration/reconstruction/tampering? The whole piece is about 6cm at its widest. I can't accurately assess the quality of preservation/prep, but to me the appearance seems consistent with other specimens, except that this one seems incompletely prepped. For the same reason I don't think there is going to be much tampering with parts still embedded in rock but I am no expert.  The seller isn't completely sure, but thinks there is no tampering other than the matrix being cut flat for display purposes. If it helps, I am waiting on some extra close-up photos of inner whorls, and maybe some photos with UV. Any thoughts? Thank you.

 

 

 

Edited July 28, 2022 by Mochaccino

[Ludwigia]

Looks genuine enough to me, although it's hard to say if the prep can be improved upon.

[Mochaccino]

36 minutes ago, Ludwigia said:

Looks genuine enough to me, although it's hard to say if the prep can be improved upon.

Thank you for assessment! Regarding prep, I was mainly thinking to clean up the matrix in the center and free up the inner whorls, and maybe also a bit of the reverse side, to really bring out the heteromorphic coiling. 

Edited July 28, 2022 by Mochaccino

[Tidgy's Dad]

The prep is awful, but may be salvageable by the look of it. 

[Mochaccino]

38 minutes ago, Tidgy's Dad said:

The prep is awful, but may be salvageable by the look of it. 

Oh yes, I'm hoping the ammonite itself hasn't been too ground up as I've been wanting one of these for a while. I'll need some better photos to be sure. Just from these I think I can make out the shine of the shell and finer ribbing, and my wishful thinking is that white crud between adjacent whorls is residual matrix that can be cleaned out. We will see.

Edited July 28, 2022 by Mochaccino

[aeon.rocks]

Hokkaido ammonites are known to be very difficult to prep, that's why it looks awful, but in fact, it's difficult to prep better in some cases; it will be tricky to improve, I'ld buy only if you like as it is.

[Mochaccino]

8 hours ago, aeon.rocks said:

Hokkaido ammonites are known to be very difficult to prep, that's why it looks awful, but in fact, it's difficult to prep better in some cases; it will be tricky to improve, I'ld buy only if you like as it is.

I see, indeed this specimen looks pretty typical of other examples of Muramotoceras I've seen online. I still do think the inner whorls may be prepped further, I'll have to see better photos.

[Mochaccino]

So I received this ammonite today, and after using some UV light on it I suspect it has spots of restoration and crack repair. The latter may be acceptable but I wouldn't want it to be restored.
 

Here in regular white light:

 

 

and here in UV:

 

As you can see, there is obvious crack repair through the piece. More concerning are patches on the ammonite that are darker+grainy in white light and fluoresce under UV.

 

Can natural substances fluoresce in this manner? To play devil's advocate, the black patches almost appear to form a layer on top of the ammonite instead of filling in missing sections; at least they seem to be in higher relief. They're also not solid/continuous masses of fluorescence but appear patchy and thin. Also, if there is restoration to fill gaps, it seems odd that there is an obvious chip in a section of the inner whorl that was not filled in:

 

I'd appreciate everyone's thoughts. Repair is acceptable, but if this is restored I might want to return it. On the other hand I could also check with something like acetone to see if that dissolves the fluorescent parts, or eventually have them prepped and removed.

 

Thank you.

 

Edited August 16, 2022 by Mochaccino