Re: Technique needed for distinguishing CaCO3 and bone

From:Philip Oshel


Pop by the EM lab -- Geology ought to have an SEM with EDX on it, or 
an electron microprobe. You want either EDX (energy dispersive x-ray 
analysis) or WDX (wavelength  dispersive x-ray analysis). These 
methods identify elements, and the EDX can map the distribution. True 
bone will show a phosphorus peak from the apatite (calcium 
phosphate), which won't appear in the calcium carbonate.
This should require minimal preparation of your samples, can 
potenially can be done museum specimens that cannot be altered, or 
can be only minimally altered (such as by carbon coating).
If Geology hasn't have such an instrument, someone at UC Boulder will 
-- it should be findable on the UC web site.


>I have several slices of bone with calcium carbonate deposited on them. I am
>searching for a good way to readily distinguish between the original bone and
>the deposited calcium carbonate. I can usually do so by visual inspection, but
>the differences are too subtle for my image analysis software to pick up. My
>goal is to be able to quantitatively determine the amount of deposition on the
>bone. If someone knows a stain or some treatment that I might be able to do
>that will help bring out the differences between the calcium carbonate and the
>bone, I will be most appreciative.
>Thanks for your help.
>Joe Daniel
>Grad student
>Museum and Field studies Program
>University of Colorado at Boulder

Philip Oshel
Supervisor, BBPIC microscopy facility
Department of Animal Sciences
University of Wisconsin
1675 Observatory Drive
Madison,  WI  53706 - 1284
voice: (608) 263-4162
fax: (608) 262-5157 (dept. fax)

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