Andrew,

Just latching on to one of your statements, namely that about pyrite
fossils and their slow (a few decades) disappearing act.  I have an
ammonite and several small oysters that are pyrite fossils.  I will have
no trouble isolating them but do you have any recommendation for
preserving them?  I had always assumed once out of the weather, they
were here for ever.  Any ideas?

Tom Eichhorst in New Mexico, USA

(Of course, in a few decades, I really won't care)