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[Gerhard Niklasch]

With my last few EURs to spend I was wandering around Ste Marie-aux-Mines and chanced upon a stall I had overlooked before.

Ooooh, Benitoite. Ok it's rare, but isn't it a bit over-hyped. But since I won't be able to afford it anyway, like Odysseus tied to the mast, why not have a look at some of it in person while I have the chance, and safely listen to its siren calls!

15 minutes and a lengthy glance with the hand lens later, I had a score of EURs less in my wallet... and called a truly tiny bit of Benitoite my own. No shapely triangular crystals here, just rudimentary hints, half sticking out of their Natrolite cradle; for a bonus, some tiny brown grains on one side are probably Joaquinite or another species of that group. (Thanks to Jordi for alerting me to them when I showed him this piece before leaving.)

Almost looks like a little blue-eyed insect from some strange planet, doesn't it?

Another acquisition at SMaM had been a UV lamp - and these baby Benitoites duly glooooooow under SWUV....

So to round this off, the last picture in this set of five is a SWUV fluorescence, stereo, photo micrograph. Bet that'll confuse the mindat picture classification system!

[Gerhard Niklasch]

Hopping from California to Peru for a moment, here's a little Baryte tablet from Cerro Warihuyn which although it can't hold a candle to Carles' magnificent yellow `Butterfly', nonetheless has its own interesting little secrets, beginning with the zones along the edges.
(It fluoresces and it phosphoresces, too, but I haven't been able to get decent pictures of either phenomenon.)
A little piece of its pink dolomitic (or dolomite-sandstone) matrix remains attached to the foot of the tablet.
First, an overview, and impressions of what it looks like under the microscope at lowest magnification (10x).
Then one evening, while I was admiring the iridescent/pearlescent reflections from lattice boundaries inside the Baryte, I accidentally turned the zoom knob in the wrong direction, racking up the magnification to 40x. My god, it's full of -- what? Tiny, lustrous, metallic-looking grains, most of poorly defined shapes, but here and there a neat octahedron among them. Given the species which are known at the site, my guess is that we're looking at Pyrite. (More to follow, stay tuned...)

[Gerhard Niklasch]

It's easier to see these Pyrite(?) inclusions `floating' just below the surface of the Baryte in the following stereo pairs.
In one area, shown in the second picture below, they were in fact left exposed on the surface and not covered by a protective final layer of Baryte, and appear to have rusted to Limonite grains.
But not only do we have these more or less equant grains everywhere under the two large tablet faces, the inclusions also occupy selected zones along the rim -- and there they are elongated along the direction of growth, perpendicular to the zone bands, even stretched diagonally wherever their enclosing zone goes around a corner. The third and fourth pair below zoom in on such an area along the upper rim. Two diagonally extended inclusions appear right of centre in the fourth shot, where the lower zone goes around its Z bend. Note also the `cloudy' disturbance in the interior of the Baryte, perhaps an ancient fracture, healed by a thin uninterrupted transparent layer forming the present surface.
The fifth pair shows diagonally-extended inclusions in one small corner near the foot of the tablet. (The overexposed thing reaching into the top right corner is one end of the attached Dolomite pebble.)
Larger versions of some of these pictures have been submitted to mindat: look for photo 244831 once it has been approved.

[Gerhard Niklasch]

While the identity of the tiny inclusions in the Peruvian Baryte remains hypothetical, octahedral Pyrite from elsewhere in the department is well known. Here's an example I recently picked up. Many of the corners show small residual facelets of the cube - but they are rectangular rather than square, so the octahedra must be slightly out of shape too, with some faces having grown a little bit quicker than others.

No two of the large triangular faces are exactly equal in texture and markings - each adds a little variety.

[Gerhard Niklasch]

Let me dwell on the octahedral shape for a bit, skipping continents and changing species...

I like this Spinel both for the anarchic growth of smaller individuals and for its improbable color! It is quite patchy, with darker, more solid-looking (and in places almost glassy) areas among the plaster-textured pink material. Not sure what the whitish patches are.

It glows a dull deep red under LW or SWUV, the darker bits more brightly so; the white stuff lights up blue under LWUV, and blueish white under SWUV.
It also phosphoresces red: A white LED is enough to excite it, but it lasts only for half a second or so.

It had some larger brothers (found in 2007), one of which is pictured here:
https://www.mindat.org/photo-175950.html

For some more background, you may wish to throw `Ipanko Spinel' at google...

[Gerhard Niklasch]

Moving to a continent closer to home and a smaller size...

Here's a Cuprite from France. Or rather, an ex-Cuprite, replaced (apparently completely[*]) by Malachite. The edges are slightly rounded; under certain lighting angles they might suggest that the departed Cuprite octahedron may have had its edges slightly beveled by the dodecahedron.

One face is decorated by a little colorless crystal - could be Calcite or perhaps some other carbonate. Some of the other faces are interrupted by a number of pits; in some of the larger pits a few individual Malachite needles can be discerned.

[* How do I know? This is left as an exercise to the attentive reader. :) ]

Did you know that Chessy-les-Mines was the type locality for Azurite?

[Jordi Fabre]

[Gerhard Niklasch]

While a few items from my drawers have served to illustrate other threads in the meantime, let's pull something from the pipeline again to post it here.

The Mogok area in Birma/Myanmar is famous for its unusual mushroom Elbaites. So how about one which is unusual for being not quite so unusual? Seems it could not quite make up its mind to grow into a full mushroom, and while some divergent growth is evident, a 3-ray star shaped block in the middle kept on growing straight, showing a neat trigonal pyramid termination and parts of a steeper trigonal pyramid around it.

The body is a deep dark wine-purple to which the camera and the gamut of computer monitors do not do full justice.

From the Kat Chay (also: Khat Che) mine, Momeik.
Specimen dimensions: 36x27x23mm, personal collection ID: 10MMT-002.
All pictures taken in direct sunlight (on a glass plate to hide the shadow from view).

Also submitted to mindat (with larger versions of some of the views) as https://www.mindat.org/photo-331007.html .