Wurtzite Polytypes from

Donohoe Station, Pennsylvania

Awesome ~2mm trigonal wurtzite with distinctive morphology.
These are the rarest and loveliest I've found. They often show
zoning phantoms at the blunt end. They are so transparent that
when looking through the scope with the light just right, an
intense total internal reflection is seen.

766. Stubby trigonal polytype. These usually are darker in
color and the xtl faces are not as smooth and lustrous as the
hexagonal polytypes. Unlike the earlier photo, note that it has
1st & second order trigonal pyramids.

767-2. 767-3. Remarkably distinct sphalerite tetrahedron
epitaxic on hexagonal wurtzite. There seems to
be some evidence of growth steps at the overhanging
sphalerite/wurtzite interface.

767-4. Two sphalerite epitaxic on hexagonal wurtzite pairs.
The sphalerite seems to have growth steps. I have observed
a few sphalerite/trigonal wurtzite epitaxies as well.

769. Rare stubby trigonal wurtzite nucleated at the edge of
a hexagonal wurtzite crystal. Nucleation at the blunt
edges & corners is not uncommon between hexagonal wurtzites.
Note also the whispy thin sphalerites. These often form
remarkble fractal-like patterns.