Dear all,
There are numerous PGE-minerals that are insuffieciently defined as "new minerals" or as oxides and hydroxides and named
as unknown minerals, because one has not been able to characterize them properly. In some cases there are only a few grains analysed by
EPMA and the material is not sufficient for complete chartacterization as demanded by IMA. In others, like Ouro Preto, Brazil, there is
plenty of material, and it should be possible to characterize the minerals sufficiently.
In my opinion we should not make a new mineral group for such natural crystalline compounds, that are not sufficiently known, yet, because it would be against most rules in mineralogy. In comparison, if we think about hydrous silicate or clay minerals they are mostly alteration minerals and people have been able to characterize them succesfully.
It is not such a long time ago when PGE-mineralogists around the world recognized that PGM are weathered in natural environments as oxides and hydroxides from primary magmatic crystals. This has also been observed from Finland in a number of cases, especially in placers. I include a few pictures of such cases: 1-2) altered braggite from the Keivitsa layered intrusion in Sodankylä, Lapland, diagrams prepared by Fernando Gervilla, University of Granada, Spain, analyses by B. Johanson, GSF, 3) sperrylite altered to native Pt and Pt-oxide, Miessijoki placer, Lemmenjoki, Finnish Lapland, analysed by Ms. S Heidrich, University of Hamburg, Germany.
best regards,
Kari K. Kojonen Ph.D.
Senior Scientist
IMA Council Member
Vice-Chairman of COM
P.O. box 96, FI-02151 Espoo, Finland
Tel. +358 20 550 2483
Mobile +358 40 753 2021
Fax +358 20 550 12
E-mail [log in to unmask]
-----Original Message-----
From: The Mineral Deposits Studies Group listserver [mailto:[log in to unmask]] On Behalf Of Jacques Jedwab
Sent: 2. joulukuuta 2008 15:42
To: [log in to unmask]
Subject: Antonil compounds
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