Associated Lapis Lazuli mineral (Afghanistan)?

While my wife is the jewelry designer, I look for raw material at bead shows. It tends to be few and far between, but at this last show, one seller had a tub of lapis lazuli. I picked out a few pieces that looked interesting. One measures 2.5x2.25x1 inch, and has one side that is clearly lapis, but the other side has white striated crystals, in addition to pyrite. Here is a close up. Mindat lists three locations in Afghanistan for lapis lazuli, but only this mine lists more minerals than just lapis. One choice is muscovite, which was my first guess, but it is crossed out and apparently not really found at that location. Any thoughts as to what the crystals really are?

Also, the seller indicated that the mine was "25 miles from Kabul" and was "8 miles long" though didn't know specifically what the name of the mine was. In looking at the mine locations on Mindat, 250 miles, rather than 25 is more reasonable, but any thoughts on what mine he may be referring to? The one that I referenced above?

Thanks to all!

C.

Probably phlogopite mica.

Nice pictures. It looks as any mica, flogopite or perhaps muscovite.

Lapislazuli is a rock composed by lazurite, afghanite, sodalite, pirite and more mixed microcrystalized minerals. Blue side of your stone could be pure lazurite. You can use a UV lamp to check if there is also sodalite (very fluorescent).

Greetings.

Josele

Thank you both! While muscovite has been crossed out at that location, phlogopite is still valid, so that would make sense. Thanks, Jose, also for the fluorescence suggestion - I just tried both shortwave and longwave UV. The blue side has no change under either, but the white side fluoresces orange under long wave, and bright pale yellow under short wave. What is the white side primarily composed of? Considering the fluorescence, calcite?

Out of curiosity, how common are macroscopic crystals of lazurite or afghanite? The lapis lazuli I'm familiar with is just the massive blue, and it would be interesting to find a crystal of either.

Thanks again,

C.

Charles, yes, white material is probably calcite, commonly asociated to lazurite. You can confirm with ClH acid test (bubbles).
Lazurite large crystals are rare around the world except in this locality in Afghanistan, as can see in lazurite Mindat gallery.
A greeting,

Josele

Jose Zendrera Wrote:
-------------------------------------------------------
> Lazurite large crystals are rare around the world
> except in this locality in Afghanistan, as can see
> in lazurite Mindat gallery.


Seeing the gallery images motivated me to track down samples for myself:

Lazurite
Afghanite

Fun stuff!

Thanks,

C.

Beautifull crystals Charles. The afghanite specimen it looks replaced by hackmanite (very fluorescent).

Josele

Jose, what is it about the specimen that looks like a hackmanite replacement?

Hi Rob, I meant the last photo of Carles:


I think, is similar to this one:


It is being sold as afghanite (and has hexagonal prism) but, to me, the high fluorescense points to hackmanite replacement.
¿What you think about?

Josele

Thanks Jose. That is Afghanite. The original material was white and I've probed similar material as afghanite.

If it helps, I just looked at my specimen under ultraviolet. Under long wave, the Afghanite appears orange, but under short wave, there is no significant effect (crystals are dark blue). I take it that it is still Afghanite, and not Hackmanite?

Thanks,

C.

Rob, I understand that this white afghanite has been analized and actually is pure afghanite.
I have a dark blue afghanite that is not fluorescent at all and another specimen blue / white mixture mostly fluorescent except dark blue parts. If is confirmed that both blue and white material are the same thing, then should occur a strong ion substitution, a solid solution or any phenomenon to explain this.
Have you any information about this?
Very thanks for your comment.
Greetings.




Josele

Thanks Charles and Jose. In Jose's excellent pictures,, which should be posted to the galleries, you have a good afghanite, white and blue. I suspect the UV photo is LW. The dark ultra marine patches that don't fluoresce are Lazurite. The white and light blue are afghanite and will give identical EDS. The lazurite probes within the bounds of Afghanite, but these opaque lazurites never fluoresce, while afghanite does. The dark opaque afghanites that don't fluoresce are either coated or replaced by lazurite. I'm currently trying to sort these out so this info is provisional. I suspect the blue fluorescent at the top is albite.

Very thanks Rob. As the original question of Charles is already answered and I do not want to change the sense of this thread, I will open a new topic to discuss this interesting matter of afghanite fluorescence. I hope to see you there!
Greetings.

Josele