<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=Windows-1252">
<style type="text/css" style="display:none;"> P {margin-top:0;margin-bottom:0;} </style>
</head>
<body dir="ltr">
<div style="font-family: "Times New Roman", Times, serif; font-size: 12pt; color: rgb(0, 0, 0); background-color: rgb(255, 255, 255);" class="elementToProof ContentPasted0">
<p class="MsoNormal" style="margin:0in 0in 8pt;font-size:11pt;font-family:"Times New Roman", serif;margin-bottom:0in">
<span style="font-size:12.0pt" class="ContentPasted1">Hi, <o:p class="ContentPasted1">
Leslie,</o:p></span></p>
<p class="MsoNormal" style="margin:0in 0in 8pt;font-size:11pt;font-family:"Times New Roman", serif;margin-bottom:0in">
<span style="font-size:12.0pt"><o:p class="ContentPasted1"> </o:p></span></p>
<p class="MsoNormal" style="margin:0in 0in 8pt;font-size:11pt;font-family:"Times New Roman", serif;margin-bottom:0in;mso-layout-grid-align:none;text-autospace:none">
<span style="font-size:12.0pt" class="ContentPasted1">I have an open source paper you might find to be of interest, a literature review of the process of pyrite oxidation and the growth of efflorescent minerals. I'm a mineralogist, so I've always thought that
if you didn't understand the minerals involved in a geologic process, you'd never understand the process. <o:p class="ContentPasted1"> </o:p></span></p>
<p class="MsoNormal" style="margin:0in 0in 8pt;font-size:11pt;font-family:"Times New Roman", serif;margin-bottom:0in;mso-layout-grid-align:none;text-autospace:none">
<span style="font-size:12.0pt"><o:p class="ContentPasted1"> </o:p></span></p>
<p class="MsoNormal" style="margin:0in 0in 8pt;font-size:11pt;font-family:"Times New Roman", serif;margin-bottom:0in;mso-layout-grid-align:none;text-autospace:none">
<span style="font-size:12.0pt;mso-ascii-font-family:"Times New Roman";mso-ascii-theme-font:major-latin;mso-hansi-font-family:"Times New Roman";mso-hansi-theme-font:major-latin;mso-bidi-font-family:"Times New Roman";mso-bidi-theme-font:major-latin" class="ContentPasted1">A
review of “pyrite disease” for paleontologists, with potential focused interventions. Palaeontologia Electronica, 23(3):a45.
<o:p class="ContentPasted1"> </o:p></span></p>
<p class="MsoNormal" style="margin:0in 0in 8pt;font-size:11pt;font-family:"Times New Roman", serif;margin-bottom:0in;mso-layout-grid-align:none;text-autospace:none">
<span style="font-size:12.0pt;mso-ascii-font-family:"Times New Roman";mso-ascii-theme-font:major-latin;mso-hansi-font-family:"Times New Roman";mso-hansi-theme-font:major-latin;mso-bidi-font-family:"Times New Roman";mso-bidi-theme-font:major-latin" class="ContentPasted1">https://doi.org/10.26879/1044<o:p class="ContentPasted1"> </o:p></span></p>
<p class="MsoNormal" style="margin:0in 0in 8pt;font-size:11pt;font-family:"Times New Roman", serif;margin-bottom:0in">
<span style="font-size:12.0pt;mso-ascii-font-family:"Times New Roman";mso-ascii-theme-font:major-latin;mso-hansi-font-family:"Times New Roman";mso-hansi-theme-font:major-latin;mso-bidi-font-family:"Times New Roman";mso-bidi-theme-font:major-latin" class="ContentPasted1">palaeo-electronica.org/content/2020/3159-pyrite-disease<o:p class="ContentPasted1"> </o:p></span></p>
<p class="MsoNormal" style="margin:0in 0in 8pt;font-size:11pt;font-family:"Times New Roman", serif;margin-bottom:0in">
<span style="font-size:12.0pt;mso-ascii-font-family:"Times New Roman";mso-ascii-theme-font:major-latin;mso-hansi-font-family:"Times New Roman";mso-hansi-theme-font:major-latin;mso-bidi-font-family:"Times New Roman";mso-bidi-theme-font:major-latin"><o:p class="ContentPasted1"> </o:p></span></p>
<p class="MsoNormal" style="margin:0in 0in 8pt;font-size:11pt;font-family:"Times New Roman", serif;margin-bottom:0in">
<span style="font-size:12.0pt;mso-ascii-font-family:"Times New Roman";mso-ascii-theme-font:major-latin;mso-hansi-font-family:"Times New Roman";mso-hansi-theme-font:major-latin;mso-bidi-font-family:"Times New Roman";mso-bidi-theme-font:major-latin" class="ContentPasted1">To
summarize for those without time to track it down. <o:p class="ContentPasted1"> </o:p></span></p>
<ol>
<li><span style="font-size:12.0pt;mso-ascii-font-family:"Times New Roman";mso-ascii-theme-font:major-latin;mso-hansi-font-family:"Times New Roman";mso-hansi-theme-font:major-latin;mso-bidi-font-family:"Times New Roman";mso-bidi-theme-font:major-latin" class="ContentPasted1">Oxidation,
reduction and hydration are reactions that involve movement of electrons. Pyrite is a semiconductor, so it moves electrons easily. In vacuum, for XPS spectroscopy, pyrite will pick up oxygen within minutes to seconds. The race against oxidation may be lost
once the pyrite is exposed to air.<o:p class="ContentPasted1"> </o:p></span></li><li><span style="font-size:12.0pt;mso-ascii-font-family:"Times New Roman";mso-ascii-theme-font:major-latin;mso-hansi-font-family:"Times New Roman";mso-hansi-theme-font:major-latin;mso-bidi-font-family:"Times New Roman";mso-bidi-theme-font:major-latin" class="ContentPasted1">Oxygen
and water work quickly to oxidize the pyrite surface. Together, they work even more quickly. The third major oxidant is Fe<sup class="ContentPasted1">3+</sup>.<o:p class="ContentPasted1"> </o:p></span></li><li><span style="font-size:12.0pt;mso-ascii-font-family:"Times New Roman";mso-ascii-theme-font:major-latin;mso-hansi-font-family:"Times New Roman";mso-hansi-theme-font:major-latin;mso-bidi-font-family:"Times New Roman";mso-bidi-theme-font:major-latin" class="ContentPasted1">Movement
of electrons, for pyrite surface oxidation, involves the oxidant, the entire body of the pyrite, and the pyrite surface. If it’s happenin’ at the surface, all the other electrons come to the party. Electrons move though the body of the pyrite and across the
surface, from Fe to Fe as well as from Fe to S. <o:p class="ContentPasted1"> </o:p></span></li><li><span style="font-size:12.0pt;mso-ascii-font-family:"Times New Roman";mso-ascii-theme-font:major-latin;mso-hansi-font-family:"Times New Roman";mso-hansi-theme-font:major-latin;mso-bidi-font-family:"Times New Roman";mso-bidi-theme-font:major-latin" class="ContentPasted1">Electron
conductivity of pyrite covers <b class="ContentPasted1">four orders of magnitude</b>. This is why some pyrites decay quickly and others don’t. Conductivity is enhanced by trace elements and vacancies in the pyrite. Trace element concentrations for pyrite also
covers four orders of magnitude.<o:p class="ContentPasted1"> </o:p></span></li><li><span style="font-size:12.0pt;mso-ascii-font-family:"Times New Roman";mso-ascii-theme-font:major-latin;mso-hansi-font-family:"Times New Roman";mso-hansi-theme-font:major-latin;mso-bidi-font-family:"Times New Roman";mso-bidi-theme-font:major-latin" class="ContentPasted1">Efflorescent
Fe<sup class="ContentPasted1">2+</sup> sulfate minerals will change hydration state quickly with changes of humidity. Fe<sup class="ContentPasted1">3+</sup> sulfates
<b class="ContentPasted1">do not lose the water</b> once it’s there. This is why humidity control alone is ineffectual. You must control oxygen as well. Dry nitrogen is probably cheapest. If you use expensive oxygen “getters”, I think you need to show that
they work faster and have a higher buffer capacity than your pyrite does. I would bet on the pyrite.
<o:p class="ContentPasted1"> </o:p></span></li><li><span style="font-size:12.0pt;mso-ascii-font-family:"Times New Roman";mso-ascii-theme-font:major-latin;mso-hansi-font-family:"Times New Roman";mso-hansi-theme-font:major-latin;mso-bidi-font-family:"Times New Roman";mso-bidi-theme-font:major-latin" class="ContentPasted1">And
BTW, Fe<sup class="ContentPasted1">3+</sup> sulfate minerals develop quickly from the initial Fe<sup class="ContentPasted1">2+</sup> sulfate minerals.<o:p class="ContentPasted1"> In my experiments, with a wekk or so. </o:p></span></li><li><span style="font-size:12.0pt;mso-ascii-font-family:"Times New Roman";mso-ascii-theme-font:major-latin;mso-hansi-font-family:"Times New Roman";mso-hansi-theme-font:major-latin;mso-bidi-font-family:"Times New Roman";mso-bidi-theme-font:major-latin" class="ContentPasted1">The
pyrite and the sulfate minerals <i class="ContentPasted1">all </i>gather a film of water as time progresses. This enhances the movement of electrons to the reaction site. It’s uncertain if the pyrite will lose that film under lower humidity conditions, but
it is <i class="ContentPasted1">certain</i> that the Fe<sup class="ContentPasted1">3+</sup> minerals will not.
<o:p class="ContentPasted1"> </o:p></span></li><li><span style="font-size:12.0pt;mso-ascii-font-family:"Times New Roman";mso-ascii-theme-font:major-latin;mso-hansi-font-family:"Times New Roman";mso-hansi-theme-font:major-latin;mso-bidi-font-family:"Times New Roman";mso-bidi-theme-font:major-latin" class="ContentPasted1">Various
coatings are ineffectual at preserving the pyrite or the fossil. They do not block oxygen or water or electron movement.
<o:p class="ContentPasted1"> </o:p></span></li><li><span style="font-size:12.0pt;mso-ascii-font-family:"Times New Roman";mso-ascii-theme-font:major-latin;mso-hansi-font-family:"Times New Roman";mso-hansi-theme-font:major-latin;mso-bidi-font-family:"Times New Roman";mso-bidi-theme-font:major-latin" class="ContentPasted1">“Neutralizing”
acid is ineffectual. Strong acids don’t just hang around waiting for a base. They react, unfortunately, with nearly anything. My experiments on the reaction between sulfuric acid and apatite (a bone analog) went so fast that I couldn’t turn around and put
the specimen on the spectrometer stage. You can <i class="ContentPasted1">watch</i> the calcium sulfate crystals grow. Also, cleaning pyrite with carbonate minerals actually enhances the pyrite surface reactions.
<o:p class="ContentPasted1"> </o:p></span></li><li><span style="font-size:12.0pt;mso-ascii-font-family:"Times New Roman";mso-ascii-theme-font:major-latin;mso-hansi-font-family:"Times New Roman";mso-hansi-theme-font:major-latin;mso-bidi-font-family:"Times New Roman";mso-bidi-theme-font:major-latin" class="ContentPasted1">Macro
does not equal micro. The actual humidity at the pyrite surface reflects the hydrous minerals present, not the ambient humidity of the air. The actual humidity depends on the film of water on the pyrite surface.
<o:p class="ContentPasted1"> </o:p></span></li></ol>
Cheers,</div>
<div style="font-family: "Times New Roman", Times, serif; font-size: 12pt; color: rgb(0, 0, 0); background-color: rgb(255, 255, 255);" class="elementToProof ContentPasted0">
Chris </div>
<div class="elementToProof">
<div style="font-family: "Times New Roman", Times, serif; font-size: 12pt; color: rgb(0, 0, 0);">
<br>
</div>
<div id="Signature">
<div>
<div style="font-family: "Times New Roman", Times, serif; font-size: 12pt; color: rgb(0, 0, 0); background-color: rgb(255, 255, 255);">
<br>
</div>
<div></div>
<div id="divtagdefaultwrapper" style="font-size: 12pt; font-family: "Times New Roman", Times, serif; color: rgb(0, 0, 0); background-color: rgb(255, 255, 255);">
<div style="font-family:Tahoma; font-size:13px">
<div style="font-family:Tahoma; font-size:13px">
<div style="font-family:Tahoma; font-size:13px">
<div class="BodyFragment" style="font-family:Helvetica"><font size="2">
<div class="PlainText"><span style="font-family: Arial, Helvetica, sans-serif;">Chris Tacker</span><span style="font-family: Arial, Helvetica, sans-serif;"><i> (he, him, his)</i></span></div>
<div class="PlainText"><span style="font-family: Arial, Helvetica, sans-serif;">Research Curator, Geology | </span><span style="font-size: small; font-family: Arial, Helvetica, sans-serif; display: inline !important; background-color: rgb(255, 255, 255);">Ph.D.</span><br>
<span style="font-family: Arial, Helvetica, sans-serif;">North Carolina Museum of Natural Sciences | 11 West Jones Street | Raleigh, NC 27601-1029</span><br>
<span style="font-size: small; display: inline !important; background-color: rgb(255, 255, 255);"><a href="http://www.naturalsciences.org/"><span style="font-family: Arial, Helvetica, sans-serif;">http://www.naturalsciences.org/</span></a></span><br style="font-family:Tahoma">
<p style="font-family: Calibri, Helvetica, sans-serif; font-size: 16px; text-align: start; margin-top: 0px; margin-bottom: 0px; background-color: rgb(255, 255, 255);">
<span style="font-family: Arial, Helvetica, sans-serif;"></span><span style="font-family:"Times New Roman",Times,serif"></span></p>
<br>
<br>
<div><a href="https://www.ncdcr.gov/" title="https://www.ncdcr.gov/"><span style="font-family: Arial, Helvetica, sans-serif;">NC Department of Natural and Cultural Resources</span></a></div>
<div><span style="font-family: Arial, Helvetica, sans-serif;">Office: </span><span style="font-family: Arial, Helvetica, sans-serif;"><strike>919-707-9941</strike></span><span style="font-family: Arial, Helvetica, sans-serif;"> </span><span style="font-family: Arial, Helvetica, sans-serif;"><i> Office
telephone and VM not currently functional</i></span></div>
<div><span style="font-family: Arial, Helvetica, sans-serif;">christopher.tacker@naturalsciences.org</span></div>
<div><br>
</div>
<div><span style="font-family: Arial, Helvetica, sans-serif;"><i>Email correspondence to and from this address is subject to the North Carolina Public
</i></span></div>
<span style="font-family: Arial, Helvetica, sans-serif;"><i>Records Law and may be disclosed to third parties</i></span><i><font size="2"><span style="font-family:Tahoma"></span></font></i><br>
</div>
</font></div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
<div id="appendonsend"></div>
<hr style="display:inline-block;width:98%" tabindex="-1">
<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>From:</b> Nhcoll-l <nhcoll-l-bounces@mailman.yale.edu> on behalf of Leslie L Skibinski <lls94@cornell.edu><br>
<b>Sent:</b> Tuesday, April 18, 2023 12:27 PM<br>
<b>To:</b> NHCOLL-L (nhcoll-l@mailman.yale.edu) <nhcoll-l@mailman.yale.edu><br>
<b>Subject:</b> [External] [Nhcoll-l] Storing and or displaying pyrite</font>
<div> </div>
</div>
<style>
<!--
@font-face
{font-family:"Cambria Math"}
@font-face
{font-family:Calibri}
p.x_MsoNormal, li.x_MsoNormal, div.x_MsoNormal
{margin:0in;
font-size:11.0pt;
font-family:"Calibri",sans-serif}
span.x_EmailStyle17
{font-family:"Calibri",sans-serif;
color:windowtext}
.x_MsoChpDefault
{font-family:"Calibri",sans-serif}
@page WordSection1
{margin:1.0in 1.0in 1.0in 1.0in}
div.x_WordSection1
{}
-->
</style>
<div lang="EN-US" link="#0563C1" vlink="#954F72" style="word-wrap:break-word">
<div style="background-color:#FFEB9C; width:100%; border-style:solid; border-color:#9C6500; border-width:1pt; padding:2pt; font-size:10pt; line-height:12pt; font-family:'Calibri'; color:black; text-align:left">
<span style="color:#FF0000; font-weight:bold">CAUTION:</span> External email. Do not click links or open attachments unless verified. Report suspicious emails with the Report Message button located on your Outlook menu bar on the Home tab.</div>
<br>
<div>
<div class="x_WordSection1">
<p class="x_MsoNormal">Hello everyone,</p>
<p class="x_MsoNormal"> </p>
<p class="x_MsoNormal">We have just gotten some fossils where the organism has been replaced with pyrite (FeS2). Because of this, they are inherently unstable and very prone to pyrite disease. Just in the short time we have had them, they have started to
become less shiny (oxidize).</p>
<p class="x_MsoNormal"> </p>
<p class="x_MsoNormal">Has anyone had experience with storing pyrite? Are there ways of packaging or storing the specimens that reduce oxygen and help maintain a stable low relative humidity? Should we use a molecular sieve or is silica gel OK. Has anyone
worked with a fabricator to design and produce a storage or exhibit case? Would storing the specimens in an anoxic environment such as storing them in nitrogen or some inert gas be feasible and reasonably cost effective?</p>
<p class="x_MsoNormal"> </p>
<p class="x_MsoNormal">Any information or suggestions would be greatly appreciated.</p>
<p class="x_MsoNormal"> </p>
<p class="x_MsoNormal">--Leslie</p>
<p class="x_MsoNormal"> </p>
<p class="x_MsoNormal"><span style="">Leslie L. Skibinski</span></p>
<p class="x_MsoNormal"><span style="">Collection Manager</span></p>
<p class="x_MsoNormal"><span style=""> </span></p>
<p class="x_MsoNormal"><span style="">Paleontological Research Institution</span></p>
<p class="x_MsoNormal"><span style="">1259 Trumansburg Road</span></p>
<p class="x_MsoNormal"><span style="">Ithaca, New York 14850</span></p>
<p class="x_MsoNormal"><span style="">Phone: (607) 273-6623 ext. 128</span></p>
<p class="x_MsoNormal"><span style="">Fax: (607) 273-6620</span></p>
<p class="x_MsoNormal"> </p>
</div>
</div>
</div>
</body>
</html>