Advice for partially pyritised ammonite prep

[fredftw]

These are two of my favourites, which I have been working on with my dremel to remove matrix. Parts of both show a fantastic golden pyrite. Sorry the pics don’t show it too well. I suspect the gold is fading however. A few questions:

 

1. Can I do anything to bring out the gold? Would polishing with a wire dremel head help?

 

2. What can I do to preserve the gold? Should I coat/seal them?

 

Thanks in advance!

[Ptychodus04]

There’s not much you can do to preserve the gold color. It is a thin layer of oxide (I believe). I’ve cleaned pyrite with iron out before and it gets really shiny but turns silver.

 

coating it will mute the colors. I have been known to coat my pyritized ammonites in Vinac or Paraloid to preserve them and prevent pyrite decay. There’s a thread on the forum on the topic of dealing with pyrite decay with hours of reading if you’re interested.