| View previous topic :: View next topic |
| Author |
Message |
Roger Warin
Joined: 23 Jan 2013
Posts: 1232
|
 Posted: Jun 01, 2013 00:32 Post subject: Re: Pyrrhotite - I lost its origin |
|
|
Hello Carles, Peter.
Thank you for these good points. I appreciate the Peter’s discussion. I think it corresponds to oxidative degradation of the initial pyrrhotite deposit.
I appreciate even more my specimen. It has a very low sulfurous odor. It has not changed in appearance in 40 years in my drawer.
You were right to insist on the presence of isomorphic phases. The basic phase diagram of Fe - S system is very complex, but a little less in space since pyrite does not appear.
Pyrrhotite also exists in meteorites (even in chondrites), but its proportions are low. It would be responsible for a remanence of magnetization in the SNC meteorites (from Mars).
Thank you.
Roger. |
|
| Back to top |
|
 |
Antonio Alcaide
Site Admin
Joined: 23 Aug 2009
Posts: 314
Location: Spain
|
| Posted: Jun 01, 2013 03:04 Post subject: Re: Pyrrhotite - I lost its origin |
|
|
| Peter Megaw wrote: | I have long been struck by the similarity of the Santa Eulalia pyrite replacements after platy pyrrhotite to those from Dalnegorsk...and wondered if the samples showing partial replacement are stable long-term or not. It's been 20 years since these flooded the market here and I would be interested to hear about collector's experiences.
As a rule of thumb I smell any pyrrhotite or pyrite pseudomorph after pyrrhotite...and even platy pyrrhotite, for traces of sulfurous odors. These tend to be unstable over time and will infect other sulfides in the same drawers. |
Thank you very much for the info, Peter. Here I am now smelling my pyrrhotites from Santa Eulalia and BTW smelling other sulphides of the collection. I have two pyrrhotites from Santa Eulalia by now. I think they are actually pyrrhotite, without replacement. One is decaying with a bad crack along the main crystal. The other looks like an old and stable specimen (no traces of sulfurous odors for this one).
My pyrrhotites from Dalnegorsk are stable.
Regards
_________________
Life is the shortest crystal |
|
| Back to top |
|
|
Jordi Fabre
Overall coordinator of the Forum
Joined: 07 Aug 2006
Posts: 5025
Location: Barcelona
|
| Posted: Jun 01, 2013 06:37 Post subject: Re: Practical Mineralogy #2: What pseudos tell us about deposit genesis - (12) |
|
|
Peter refreshed my memory, I found the discussion mentioned by Peter and I unified it with this new post. The result was so exciting that I upgraded the whole combo to the Featured Columns of FMF section and I renamed it as: "Practical Mineralogy #2: What pseudos tell us about deposit genesis - (12)"
Great posts / topics Peter. Thank you so much! |
|
| Back to top |
|
|
|
FAQ 
Register
Log in
Forgotten your password?
