FTIR is a quick and easy way of differentiating calcite and
aragonite. It only requires 1.5mg of material using KBr disks.
However, although I don't know the precision offhand  I don't
believe it's as good as that mentioned by Kathryn for ESR.

Julia Lee-Thorp

> Hello all.  Would anyone care to comment on their experiences with
> non-XRD- and non-optical-based methods for discriminating between
> aragonite and calcite, particularly their relative proportions in
> small powdered samples?  Thanks, Stephen
> --
> <><><><><><><><><><><><><><><><><><><><
>
> Stephen A. Schellenberg
> Institute of Marine Sciences
> University of California
> 1156 High Street - EMS-A232
> Santa Cruz, CA 95064
>
> 831.459.3123 - Lab
> 831.459.3074 - Fax
>
>
Julia Lee-Thorp
Associate Professor
Faculty of Science
University of Cape Town
P/B Rondebosch 7701
South Africa
Tel. 027-21 6502350
Fax. 027-21 6502352