Skip to main content


Spectra for Calcium (Ca)

C-K edge and Ca L2,3 Edges recorded from CaCO3 in the shell of the Pinna Noblus Mollusk. The Nacre has an Aragonite structure, and the Prism has a calcite structure. The differences between these two phases can be seen in the Ca L edge at higher dispersion. The C-K edge shows a strong excitonic peak at the edge onset that narrows the Pi* peak into a sharp line well separated from the main body. This is indicative of a very ionic material. From R. Hovden et al., “Nanoscale Assembly Processes Revealed in the Nacroprismatic Transition Zone of Pinna Nobilis Mollusc Shells” Nature Communications 6, (2015): 10097

By: Robert Hovden Microscope:

200 keV FEI Tecnai F20 equipped with a Gatan imaging filter 865-ER 

Energy Resolution: 0.5eV