Stibiotantalite (fine thumbnail)

Minas Gerais, Brazil
Ex. Brian Kosnar
Thumbnail, 1.4 x 1.2 x 0.8 cm
Start Time: 03/16/2023 7:00:00 pm (CDT)
End Time: 03/23/2023 6:45:00 pm (CDT)
Auction Closed
Winning Bid: $136

Item Description

Stibiotantalite is a rare antimony tantalum niobium oxide species, most famously found at the Himalaya Mine in California. Specimens from Brazil are exceedingly rare, and this particular piece is one of only a few I've seen from the entire country. I honestly can't remember seeing a better thumbnail from Brazil. This piece is a fine, sharp, very well-formed, somewhat thick, orthorhombic crystal with lustrous, smooth faces, especially on the termination. The piece is essentially black and opaque, as I could not get any light to come through even with strong backlighting, but there is a slight dark yellowish hue on the underside, which is indicative of Stibiotantalite, which often has some kind of yellow hue. I looked at the piece with a loupe, and I can't find any damage on the termination, though the crystal is contacted on the underside. It's a truly impressive and worthwhile example of a mineral that is seldom seen from Brazil, and would make a great addition to any thumbnail or rare mineral collection. This piece was mined in the late 1990s and comes from the collection of Brian Kosnar. It's hard to put a fair market value on a piece like this, but I hold it in high regard for its quality and rare locality.

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Bidding History

Bid Amount Bid Time
$136 03/23/2023 6:26:10 pm (CDT)
$126 03/23/2023 6:26:10 pm (CDT)
$116 03/23/2023 6:26:02 pm (CDT)
$106 03/23/2023 6:26:02 pm (CDT)
$96 03/23/2023 1:42:26 pm (CDT)
$86 03/23/2023 1:42:26 pm (CDT)
$61 03/22/2023 6:51:11 am (CDT)
$51 03/22/2023 6:51:11 am (CDT)
$36 03/18/2023 7:34:26 am (CDT)
$31 03/18/2023 7:34:26 am (CDT)
$26 03/18/2023 1:46:33 am (CDT)
$21 03/18/2023 1:46:33 am (CDT)
$10 03/17/2023 7:36:43 pm (CDT)