[NHCOLL-L:3418] RE: light levels for mineral specimens

[Demouthe, Jean]

Dear Cherry:

 

Light damage to minerals depends on the intensity and wavelengths of the
light, its duration, and the mineral species involved.  Heat can also be a
factor if your light sources are close to or contained with the display
cases.  

 

The damage may consist of fading only, but some minerals will deteriorate
physically when exposed to certain wavelengths of light.  Light damage is
permanent and irreversible.  So if you are concerned about a particular
specimen,  keep the light low and cool, or do not display it at all.

 

If you are planning a mixed exhibit that includes both susceptible and
non-susceptible mineral species, you may have to compromise on your lights.


 

You might want to look at Frank Howie's book The Care & Conservation of
Geological Material (Butterworth-Heinemann, 1992).  There is an article there
by Kurt Nassau on conserving photosensitive minerals and gems.  There is also
a good article by Rob Waller on dealing with specimens that are sensitive to
temperature and humidity, which may also affect your specimens on exhibit.

 

Good luck!

 

Jean DeMouthe

 

 

**********************

Dr. J.F. DeMouthe

Senior Collections Manager for Geology

California Academy of Sciences

875 Howard Street

San Francisco, CA  94103

phone: 415-321-8258

e-mail: jdemouthe at calacademy.org

 

-----Original Message-----
From: owner-nhcoll-l at lists.yale.edu [mailto:owner-nhcoll-l at lists.yale.edu] On
Behalf Of Cherry Johnson
Sent: Thursday, April 26, 2007 9:09 AM
To: NHCOLL-L at lists.yale.edu
Subject: [NHCOLL-L:3415] light levels for mineral specimens

 

Hi All,

Could anyone advise as to preferred light levels for exhibiting minerals.  

Obviously, there are some that can be really damaged by light and some not so
much.  Any input would be helpful.

Thanks,

Cherry

 

 

 

Cherry Johnson

Collections Manager

Weinman Mineral Museum

PO Box 3663

Cartersville, GA  30120

770-386-0576 x 405

770-386-0600 fax

 

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