I was so pleased with how the Marcasite sphere turned out.  Then I find out the material has major issues.

It turns out Marcasite has a tendency to "rot" when exposed to moisture.  I contacted a sphere maker I know that has made many Nipomo Marcasite spheres.  In the discussion, he said the material rots from the inside out.  He "cooks" the material to completely to remove any internal moisture and then seals all vugs and pits completely with resin.  

This sphere will now become an experiment in my personal collection.  The boulder it came from had sat outside in the elements (snow and rain) for 6 years and is from Indonesia.  That might make a difference?  Time will tell.