[Rockhounds] 18 sided Beryl crystal

[Kreigh Tomaszewski]

I found an 18 sided specimen on MinDat at https://www.mindat.org/gl/6805
(look in the upper right corner) that is a better picture.

On Tue, Mar 5, 2019 at 5:20 PM Peter Richards <rpr at heidelberg.edu> wrote:

> Sorry to say that the pictures are not detailed enough to show anything
> distinctive about the morphology.  But these do look like an undistorted
> crystal.  If they have 18 prism faces, as you say, they probably have a
> combination of a hexagonal prism and a di-hexagonal prism.  That’s pretty
> exciting - I’ve never actually seen a beryl crystal like that.  However, it
> is a single crystal of unusual morphology, not a twinned crystal.
>
> I hope you find the specimen!
>
> Pete
> ___________________________
> R. Peter Richards, Ph.D.
> rpr at heidelberg.edu
> Morphological Crystallographer
>
> > On Mar 5, 2019, at 5:03 PM, Kreigh Tomaszewski <kreigh at gmail.com> wrote:
> >
> > I could not find the specimen, but I found a couple pictures (sent to
> Peter
> > off list). Mine was actually an 18 sided crystal (not 12 as I
> remembered).
> >
> > On Tue, Mar 5, 2019 at 4:46 PM Peter Richards <rpr at heidelberg.edu>
> wrote:
> >
> >> 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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