Ferrokesterite / (exceptionally superb twin) on Andorite / Locality - San Jose Mine, Oruro City, Cercado Province, Oruro Department Bolivia


Shipping to United States: Free

This is a very rare MATRIX specimen featuring a penetration twin of Ferrokesterite measuring 1.8 cm at its longest dimension sitting on bladed/layered Andorite crystals and thin "needles" of Zinkenite. The Ferrokesterite has excellent crystal form with a silvery-black exterior and very good luster for the species. The Andorites show that classic "gun metal" hue and are notably well-crystallized with the classic "layered" growth. Together with the Zinkenite, they comprise a very rare combination/association specimen. I have only seen three pieces of Ferrokesterite on Andorite like this. This particular piece is the best and most aesthetic specimen I have seen from this locality, and has remained in my personal Bolivian collection for many years. To have the best of any species is certainly rare, but when it's combined with the fact that the crystals are superb penetration twins on matrix, makes it all the more enticing. Another significant feature of the piece is that this is an incredibly rare sulfide, and the crystals aren't micros! You can clearly see them with the naked eye, which is remarkable when one is talking about such a rare species (it's only found in about 12 places in the world). Perhaps the most important aspect of the piece is that it is nearly a complete "floater"!! It's literally crystallized nearly all the way around with only a tiny contact on the bottom, but the rest of the specimen is undamaged! I will reiterate that this association is extremely rare, and to find a piece with such superb aesthetics is astounding. For anybody who has ever wanted a superb piece of this remarkable material from this famous, historic, 500+ year old mine, this is arguably the finest matrix example that I have had to offer.

ex Brian Kosnar collection

Locality: San Jose Mine, Oruro City, Cercado Province, Oruro Department Bolivia

Specimen Size: 3.7 x 2.5 x 2.3 cm (miniature)
Ferrokesterite Twin: 1.8 cm across

PLEASE READ the FULL STORY that I wrote several years ago on these pieces, at this link: https://mineralclassics.patternbyetsy.com/blog

Shipping from United States

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