[NHCOLL-L:4479] Re: Mould on fossils

[Demouthe, Jean]

We encountered similar problems in some fossils from the Stanford Univ. collection.  These specimens had been mounted in plaster, and then framed in wood.  Over the years, they got wet several times.  Some of the gypsum (plaster) recrystallized on the surface of the specimens.  In a few cases, there was also mold involved, which appeared to be mostly in and on the old wooden frames.

We dealt with this by removing the frames, and cleaning the mold and efflorescence using dry brushes and a HEPA vacuum.

You should check to see if there is any plaster or other support medium involved, and take those materials into consideration when planning your conservation methods.

I hope this helps.

Jean DeMouthe

Dr. Jean F. DeMouthe
Senior Collections Manager for Geology
California Academy of Sciences
55 Music Concourse Drive, Golden Gate Park
San Francisco, California 94118
jdemouthe at calacademy.org<mailto:jdemouthe at calacademy.org>
(415) 379-5258



From: owner-nhcoll-l at lists.yale.edu [mailto:owner-nhcoll-l at lists.yale.edu] On Behalf Of Shelton, Sally Y.
Sent: Monday, August 31, 2009 7:39 AM
To: Simmons, John; hfourie at nfi.museum
Cc: nhcoll-l at lists.yale.edu
Subject: [NHCOLL-L:4477] Re: Mould on fossils

I would also check to make sure that, as John says, this is not Byne's "disease" or other mineral efflorescence. The scenario you describe does not sound like pyrite breakdown, but does suggest the possibility of mineral efflorescence.

I hate to engage in shameless self-promotion and am not trying to do so, but here is a reference: http://www.nps.gov/history/museum/publications/conserveogram/11-15.pdf. This can affect fossil as well as Recent specimens.


Sally Y. Shelton, Collections Manager and Faculty Instructor
Museum of Geology, O'Harra 307
South Dakota School of Mines and Technology
501 E. St. Joseph
Rapid City, SD   57701
phone 605.394.2487
email Sally.Shelton at sdsmt.edu



From: owner-nhcoll-l at lists.yale.edu [mailto:owner-nhcoll-l at lists.yale.edu] On Behalf Of John E Simmons
Sent: Monday, August 31, 2009 8:14 AM
To: hfourie at nfi.museum
Cc: nhcoll-l at lists.yale.edu
Subject: [NHCOLL-L:4476] Re: Mould on fossils

Are you positive that this is mold?  Mold needs a nutrient base to grow, as well as high humidity (>65% for most species).  There are very little nutrients on fossils, unless the mold is eating some organic-based coating.   You might be seeing a salt efflorescence or crystallization of minerals in the rock matrix (e.g., pyrite disease) rather than mold--try scraping some off and looking at it under a microscope.

--John

John E. Simmons
Museologica
128 E. Burnside Street
Bellefonte, Pennsylvania 16823-2010
simmons.johne at gmail.com<mailto:simmons.johne at gmail.com>
303-681-5708
www.museologica.com<http://www.museologica.com>
and
Adjunct Curator of Collections
Earth and Mineral Science Museum & Art Gallery
Penn State University
19 Deike Building
University Park, Pennsylvania 16802-2709
jes67 at psu.edu<mailto:jes67 at psu.edu>
---------- Forwarded message ----------
From: Dr Heidi Fourie <hfourie at nfi.museum<mailto:hfourie at nfi.museum>>
Date: Sat, Aug 29, 2009 at 7:36 AM
Subject: [NHCOLL-L:4474] Mould on fossils
To: nhcoll-l at lists.yale.edu<mailto:nhcoll-l at lists.yale.edu>
I've discovered mould growing on fossils we stored in our basement.  These are invertebrate fossils in blocks mounted in wooden frames.  Both the frame and fossil are covered in mould.  The mould is  whitish grey wooly and round in pattern.  It even grows on the Glyptal.
My question is, what is the safest chemical to clean this with or is water and soap safest.  The storage room that it is going to has a very low humidity so I don't think the mould will reappear and how safe is the fossil plants in the same basement storeroom?

Heidi
Dr H. Fourie
Curator: Vertebrate Palaeontology
Transvaal Museum
Tel: 012 3227632



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