Re care of meteorites: I am posting this to the list as well because this
question has come up before.
A lot depends on the nature of your collections and its use, as well as
the chemical composition of your particular specimen. In general, I
recommend not using any kind of surface coating or lacquer unless there
is an overwhelming reason for doing so. It introduces a chemical
contaminant that may be difficult or impossible to remove for future
studies, and these coatings very seldom hold up well. If they have any
tendency to cross-link and shrink at all, they will deteriorate readily.
If they admit any oxygen or water vapor at all, they are in effect doing
nothing. They may give a surface gloss to the surface of the meteorite
(or a cut and polished face of it), but don't really do what you want
them to in the long run. If the meteorite is coated and then put in a
dusty area, the coating will pick up particulate pollution if if softens
in warm conditions (I've seen this happen all too often) and the dirt
will be irretrievably embedded, obscuring the features of the meteorite
and making removal of the coating necessary.
Your storage conditions should be sufficient to keep the specimen in
dark, cool, dry (RH less than 50%) conditions. Beyond providing a stable
storage environment (and I count exhibition as visible storage
conditions), you should know what kind of meteorite you have and how
reactive it is. Stony ones are often less reactive than metallic ones,
but each is very different.
If you have a reactive meteorite and less-than-ideal storage conditions
(and who doesn't?), I recommend anoxic microenvironments as described by
John Burke of the Oakland Museum in the WAAC Newsletter. Chris Collins
of the Geological Conservation Unit, Cambridge University, and I have
experimented for two years now with this approach to managing
environmentally reactive geological specimens, and it works
beautifully. This entails heat-seal anoxic film plus an oxygen scaenger
such as Ageless. I will send details off-list to anyone who asks. It is a
relatively inexpensive way to create an anoxic environment immediately
around the specimen, and drastically slows down the rate of deterioration.
There is a chapter on meteorite conservation in the Butterworths book
*Conservation of Geological Material,* edited by Frank Howie, which I
also recommend.
Lacquer makes you think you have solved a problem, but in reality it
only treats the symptoms. It does nothing to solve the problem and may
create its own problems over time. The Burke approach blocks the major
problem at its source. You still have to keep an eye on the thing and
replace the oxygen scavenger as necessary, and the specimen will be in
its bag unless you remove it. If part of your plan is to fondle the
specimen a lot, you may not like this.
Lastly, I don't recommend doing anything you don't have to do. The above
recommendations are for specimens with observed deterioration. If it
ain't broke.....for heaven's sake, don't coat it.
Sally Shelton
Director, Collections Care and Conservation
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On Mon, 3 Jul 1995, Chris Lee wrote:
> Does anyone out there know the best way to keep an iron meteorite
> from rusting. I recently noticed some buildup on my little one. I
> purchased it at a gem and rock shop last year for myself. I thought
> about coating it with laquer but I've hesitated until I could find out
> what the conventional wisdom was.
>
> Since the meteorite is a personal possession I suppose it might be better
> to respond to me via email. My address is [log in to unmask] If members
> of museum-l are interested I will post responses.
>
> Thanks in advance,
> Chris Lee
>
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