Not all X-ray machines are shaped like dental X-ray machines.
Sedimentologists use a high-powered, commercially available version that
completely encloses the sample and film in an oven-like, lead-lined box.
Film is available in many standard sizes, and in many kinds adapted to
different uses, but ordinary medical films should work well for shells.
Because of the need for heavy lead lining (in the box or in an apron), the
machines are hardly portable.
 
Arnold Bouma included a chapter on the geologic uses of X-rays in his book
on sedimentologic techniques, with many pointers that could only have been
gained by experience. I'll look up the reference if people are interested.
It's not the kind of thing that most people would want to set up in the
home.
 
If I may make a suggestion: One of Conch-L's dealers could supply one of
our medical conchologists with examples of fake shells for X-raying. This
would make a really interesting set of images for publication.
 
As to guavas <sigh>, they are a favorite of mine, though they are not often
available here and I usually content myself with guava jam instead. The
flavor is complex and subtle, and there are many kinds. But some tropical
fruits have surprising vernacular connotations <wink> and I was wondering
what extra meanings, if any, Emilio intended. After "conchas," I have
learned that one must choose one's words carefully in Latin America. And on
Conch-L. <grin>
 
Andrew K. Rindsberg
Geological Survey of Alabama
Tuscaloosa, Alabama, USA (warm at 33 N latitude, but not tropical)