[Rockhounds] when volcanoes drop bombs: giant crystal payload

[Earl R. Verbeek]

Great photos and specimen, Don -- thanks for posting.  Red fluorescence is
due to Fe3+ substituting for Al3+ in the feldspar structure and is common
worldwide.  Hardly ever bright, but strikingly beautiful.  Best I know of,
almost bright enough to be displayable, is in paracelsian from Bennallt
mine, Caernarvonshire, Wales (hope I got the spelling right).  But I think
you knew all that from our days of running the spectrophotometer back here
in NJ.

        Cheers-   Earl

----------------------------------- 
Earl R. Verbeek, Resident Geologist 
Sterling Hill Mining Museum 
30 Plant St., Ogdensburg, NJ  07439 
973-209-7212 
shmm at ptd.net


-----Original Message-----
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[mailto:rockhounds-bounces at lists.drizzle.com] On Behalf Of DonH
Sent: Wednesday, August 01, 2007 1:31 AM
To: rockhounds at lists.drizzle.com
Subject: [Rockhounds] when volcanoes drop bombs: giant crystal payload