<html><body><div style="color:#000; background-color:#fff; font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:10pt">Hi Jean,<br><br>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.<br><br>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.<br><br>Regards,
Paul<br><div><span><br></span></div><div> </div><div>P.C. Nascimbene <br>Paleoentomological Research and Collections<br>Division of Invertebrate Zoology <br> American Museum of Natural History<br>79th Street at Central Park West<br>New York, NY 10024 USA<br></div> <div style="font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 10pt;"> <div style="font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 12pt;"> <div dir="ltr"> <hr size="1"> <font face="Arial" size="2"> <b><span style="font-weight:bold;">From:</span></b> "Demouthe, Jean" <JDemouthe@calacademy.org><br> <b><span style="font-weight: bold;">To:</span></b> "nhcoll-l@mailman.yale.edu" <nhcoll-l@mailman.yale.edu> <br> <b><span style="font-weight: bold;">Sent:</span></b> Friday, March 28, 2014 2:24 PM<br> <b><span style="font-weight: bold;">Subject:</span></b> [Nhcoll-l] freezing
amber<br> </font> </div> <div class="y_msg_container"><br><div id="yiv4967147964">
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<div class="yiv4967147964MsoNormal"><span style="font-size:12.0pt;">Dear Colleagues:</span></div>
<div class="yiv4967147964MsoNormal"><span style="font-size:12.0pt;"> </span></div>
<div class="yiv4967147964MsoNormal"><span style="font-size:12.0pt;">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.</span></div>
<div class="yiv4967147964MsoNormal"><span style="font-size:12.0pt;"> </span></div>
<div class="yiv4967147964MsoNormal"><span style="font-size:12.0pt;">I am looking for information or references on the effects of freezing and/or repeated freezing on amber.</span></div>
<div class="yiv4967147964MsoNormal"><span style="font-size:12.0pt;"> </span></div>
<div class="yiv4967147964MsoNormal"><span style="font-size:12.0pt;">Assume the conditions are: 48 hours at <0<sup>o</sup> C.</span></div>
<div class="yiv4967147964MsoNormal"><span style="font-size:12.0pt;"> </span></div>
<div class="yiv4967147964MsoNormal"><span style="font-size:12.0pt;">Any help you can give me will be greatly appreciated.</span></div>
<div class="yiv4967147964MsoNormal"><span style="font-size:12.0pt;"> </span></div>
<div class="yiv4967147964MsoNormal"><span style="font-size:12.0pt;">Jean
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<div class="yiv4967147964MsoNormal"><span style="font-size:12.0pt;"> </span></div>
<div class="yiv4967147964MsoNormal"><span style="font-size:12.0pt;"> </span></div>
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<div class="yiv4967147964MsoNormal"><i><span style="font-size:10.0pt;color:#4F6228;">Dr. Jean F. DeMouthe</span></i></div>
<div class="yiv4967147964MsoNormal"><i><span style="font-size:10.0pt;color:#4F6228;">Senior Collections Manager for Geology</span></i></div>
<div class="yiv4967147964MsoNormal"><i><span style="font-size:10.0pt;color:#4F6228;">California Academy of Sciences</span></i></div>
<div class="yiv4967147964MsoNormal"><i><span style="font-size:10.0pt;color:#4F6228;">55 Music Concourse Drive</span></i></div>
<div class="yiv4967147964MsoNormal"><i><span style="font-size:10.0pt;color:#4F6228;">San Francisco, California 94118</span></i></div>
<div class="yiv4967147964MsoNormal"><i><span style="font-size:10.0pt;color:#4F6228;">415-379-5258</span></i></div>
<div class="yiv4967147964MsoNormal"><i><span style="font-size:10.0pt;color:#4F6228;">jdemouthe@calacademy.org</span></i></div>
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