Potential Mold on a fossil

[Othniel C. Marsh]

Below is a small fossil that I think may have some mold on it. Is it actually mold, and if it is, how do I address this?

 

[Kane]

Not quite seeing mold here, but one method in removing mold in general might be household bleach. 

[North]

Would you be able to get more focused picture on area you suspect?

Did you just receive your fossil or have you had it for awhile?

[digit]

That looks like an Oligocene mandible (fragment) of the rodent Ischyromys from the Brule Formation in Nebraska. I've just been working last week on identifying and cleaning many Nebraska surface-hunted specimens from the Badlands in the FLMNH collection so this looks familiar. I noticed many that had areas speckled with tiny (even under a microscope) black spots. These were on specimens in climate-controlled conditions for up to 2 decades so I don't believe them to be active mold (if this is similar to what you are seeing). We get a more substantial covering of black on some of the fossil material from the Montbrook site in Florida that seems to be from manganese precipitation. Perhaps, the black speckling is nothing more than tiny amounts of mineral precipitation. You can try cleaning it with acetone and a small artist's paintbrush. That works for the Montbrook material and may remove the specking you are concerned with. It has not been an issue with the FLMNH specimens and the only prep we do is using a pin-vise to remove tiny amounts of matrix from around the dentition to make it more diagnostically visible.

 

 

Cheers.

 

-Ken

[Othniel C. Marsh]

2 hours ago, digit said:

That looks like an Oligocene mandible (fragment) of the rodent Ischyromys from the Brule Formation in Nebraska. I've just been working last week on identifying and cleaning many Nebraska surface-hunted specimens from the Badlands in the FLMNH collection so this looks familiar. I noticed many that had areas speckled with tiny (even under a microscope) black spots. These were on specimens in climate-controlled conditions for up to 2 decades so I don't believe them to be active mold (if this is similar to what you are seeing). We get a more substantial covering of black on some of the fossil material from the Montbrook site in Florida that seems to be from manganese precipitation. Perhaps, the black speckling is nothing more than tiny amounts of mineral precipitation. You can try cleaning it with acetone and a small artist's paintbrush. That works for the Montbrook material and may remove the specking you are concerned with. It has not been an issue with the FLMNH specimens and the only prep we do is using a pin-vise to remove tiny amounts of matrix from around the dentition to make it more diagnostically visible.

 

That's exactly what this little fella is- an Ischyromys typus partial jaw. Thanks for the clarification, digit. I'll try the acetone-paint-brush technique at some point and see what happens.

[digit]

1 hour ago, Othniel C. Marsh said:

I'll try the acetone-paint-brush technique at some point and see what happens.

Thanks. I'm curious if it would clean up those tiny black speckles that I've seen on probably 40 specimens--never completely covered with them but usually on one corner. Odd that.

 

1 hour ago, Othniel C. Marsh said:

That's exactly what this little fella is- an Ischyromys typus partial jaw.

A surprisingly large squirrel-like early rodent. Easy to distinguish from the other rodentia from Nebraska in the collection.

 

https://www.dmr.nd.gov/dmr/sites/www/files/documents/paleontology/pdfs/prehistoric-life-map/Ischyromys.pdf

 

 

Cheers.

 

-Ken