[Nhcoll-l] freezing amber

[Anderson, Gretchen]

Jean-
I agree with Paul, freezing amber is generally a bad idea.  My question to you is why are the entomologists freezing amber?  If it standard protocol for pest control, they need to understand that specimens that are not sensitive to pest damage, such as amber, do not need to be frozen.  It could cause damage, and it is also a waste of resources (time and money). Freezing resins can be done safely (double bagging etc) but why do it if you don't have to.

I suggest that the protocols be adapted to make amber the exception rather than the rule.

Good luck!
Gretchen

Paul, - thanks for the article!

________________________________
From: nhcoll-l-bounces at mailman.yale.edu [nhcoll-l-bounces at mailman.yale.edu] on behalf of Paul Nash [cedarsap at yahoo.com]
Sent: Friday, March 28, 2014 10:08 PM
To: Demouthe, Jean; nhcoll-l at mailman.yale.edu
Cc: Dave
Subject: Re: [Nhcoll-l] freezing amber

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Hi Jean,

Freezing amber is a bad idea.  Amber pieces often contain bubbles of liquid.  Because water expands when frozen, freezing and thawing amber will likely crack and damage pieces along with their arthropod inclusions. It is even possible for inclusions themselves to contain liquid. And due to the chemical nature of fossil resins (as natural polymers), freezing and thawing could have other deleterious effects. In fact, it is a general rule that significant temperature fluctuations will compromise amber specimens over time.

I've attached a paper on deterioration in fossil resins that addresses conservation protocols. Hope this helps, and please feel free to contact me if you have further questions.

Regards, Paul


P.C. Nascimbene
Paleoentomological Research and Collections
Division of Invertebrate Zoology
American Museum of Natural History
79th Street at Central Park West
New York, NY 10024 USA
________________________________
From: "Demouthe, Jean" <JDemouthe at calacademy.org>
To: "nhcoll-l at mailman.yale.edu" <nhcoll-l at mailman.yale.edu>
Sent: Friday, March 28, 2014 2:24 PM
Subject: [Nhcoll-l] freezing amber

Dear Colleagues:

Most of our amber is held by the Entomology department, who freeze everything before putting it in the collection room.  Every time anything goes out, it gets refrozen.

I am looking for information or references on the effects of freezing and/or repeated freezing on amber.

Assume the conditions are:  48 hours at <0o C.

Any help you can give me will be greatly appreciated.

Jean




Dr. Jean F. DeMouthe
Senior Collections Manager for Geology
California Academy of Sciences
55 Music Concourse Drive
San Francisco, California 94118
415-379-5258
jdemouthe at calacademy.org


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