[Rockhounds] Puzzle

[Axel Emmermann]

Carolyn,

I looked at Mindat to find the inventory of the Havey Quarry. It turns out
that there are Havey Quarry #1 and #2 listed as well as the Berry-Havey
quarry.
In the latter there is bertrandite to be found. 
You didn't mention the size of the crystal. If it's not too big, bertrandite
would be a possible. It's not hexagonal but it can sometimes appear to be. I
have no idea how much experience you have (for all I know you may be a
professional geologist ;-)))
If this http://www.mindat.org/photo-236703.html was sitting on a matrix in
the shown position it could fool me for a couple of minutes.
This one looks even more hexagonal : http://www.mindat.org/photo-14746.html
Even more misleading: http://www.mindat.org/photo-148802.html

Bertandite scores 6-7 on Moh's scale... close enough?
On the other h	and: if you managed to measure a hardness of 7.5 with some
confidence the crystal (probably more than one?) must have been sufficiently
large to do so.
One would also expect a greenish fluorescence rather than a blue one if I'm
not mistaken?

I think that the best guess is still feldspar, though.
A photo would take us a long way....

Cheers
Axel

 
> -----Oorspronkelijk bericht-----
> Van: rockhounds-bounces at lists.drizzle.com
[mailto:rockhounds-bounces at lists.drizzle.com]
> Namens Carolyn Reynard
> Verzonden: zondag 12 juli 2009 20:45
> Aan: Rockhounds
> Onderwerp: [Rockhounds] Puzzle
> 
> To the List: I have and interesting puzzle.
> 
> I collected the specimen at the Havey Quarry, Oxford Maine.
> 
> It is a crystal that appears to be common beryl as you can determine the
hexagonal crystal
> shape.  The hardness is
> 7.5.  The color is a warm light tan.  The matrix is feldspar.
> 
> What doesn't quite convince me it is a  beryl is a texture that looks
likes like perthite and
> runs the complete length of the crystal into part of the matrix and is at
right angles to the C
> axis. The feldspar matrix fluoresces at bright light blue with red
perthitic texture as does
> this crystal..
> 
> I am wondering if this specimen is a pseudomorph, with perthitic
microcline after beryl.
> Would the microcline replacement still retain the hardness of the beryl?
> 
> I believe this is the important question.  Certainly the crystal
fluoresces like the microcline
> but there is the problem of hardness being too great for a feldspar.
> 
> Nice specimen, just wish I could figure it out!
> 
> Carolyn Reynard
> 
> 
> 
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