[Rockhounds] 18 sided Beryl crystal

[Peter Richards]

I may rapidly become viewed as a crystallographic curmudgeon, but I will report that twinning is not known in beryl.  Kreigh, can you provide more description and maybe a picture somewhere?

Pete Richards
___________________________
R. Peter Richards, Ph.D.
rpr at heidelberg.edu
Morphological Crystallographer

> On Mar 5, 2019, at 3:31 PM, Kreigh Tomaszewski <kreigh at gmail.com> wrote:
> 
> I have a small 12 sided crystal from the same locality that is a twinned
> crystal, and the faces are pretty close to being even. Your's looks more
> like a group of crystals that grew together, but not quite in the same axis
> alignment.
> 
> On Tue, Mar 5, 2019 at 2:47 PM <larryrush at att.net> wrote:
> 
>> I acquired this piece many years ago, in a trade. It may be described as a
>> hexagonal tripyramid (?). Although it does have 18 prism faces, few are of
>> the same width, and the symmetry is not obvious or easily defined.  The
>> locality is the Mc Ginnes Mine, Wentworth, Grafton Co., NH, noted for these
>> unusual beryls. It is 2X3X13 cm in size, and has no terminations.
>> 
>> 
>> 
>> I got it due to its unusual habit, and would appreciate any comments that
>> help to define it, crystallographically.
>> 
>> 
>> 
>> <https://www.irista.com/gallery/sdsy1wlie6l5>
>> https://www.irista.com/gallery/sdsy1wlie6l5
>> 
>> Larry
>> 
>> 
>> 
>> Larry Rush
>> 
>> BS Geology
>> 
>> ConnRox Minerals
>> 
>> Guilford, CT
>> 
>> 
>> 
>> 
>> 
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