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Weddellite

Posted by Rock Currier  
avatar Weddellite
November 04, 2008 12:03PM
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Can you help make this a better article? What good localities have we missed? Can you supply pictures of better specimens than those we show here? Can you give us more and better information about the specimens from these localities? Can you supply better geological or historical information on these localities?


Weddellite
Ca(C2O4)●2H2O tetragonal
The mineral was first discovered in sediments dredged from 4434 to 5008 meters in the Weddell Sea near Antarctica. The crystals were extremely sharp and range in size from 0.2 x 0.1 x 0.15 mm.1 Fine transparent sharp amber colored micro crystals associated with colorless fluorite are found in England at the Milltown Quarry, but the best crystals by an oder of magnitude are those from Oregon, USA. There are more than 15 other localities and many of them are associated with organic remains in sedimentary settings. Frondell & Prien (1942 noted that weddellite was very abundant in human urinary calculi (kidney stones).3
1. Canadian Mineralogist, Vol. 21, p.503-511, Weddellite from Biggs, Oregon, USA, J.A. Mandarino & Nobel V. Witt
2. Handbook of Mineralogy, Volume V, , Anthony, Bideaux, Bladh, Nichols, p750
3. Frondel, C. & Prien, E. L. (1942); Carbonate-apatite and hydroxyl-apatite in urinary calculi. Science 95, 431.


Weddellite
UK
England, Derbyshire, Ashover, Milltown, Milltown Quarry
Weddellite xl. 0.75mm on Fluorite© Steve Rust


We need someone to tell us about the Weddellite specimens from this locality.


Weddellite
United States
Oregon, Sherman County, West of Biggs, Fulton Canyon Quarry, Isami (Sammi) Tsubota jasper mine
Weddellite xl ~3cm tall©


It would appear that this locality produced by far the largest and most agree the best crystals of weddellite. “Crystals up to 5x5x40 mm occur in cavities, often a single crystal in a cavity. They are usually tan in color but sometimes have white fibrous aggregates of weddellite growing on them.”1 The crystals are dull to vitreous in luster and often have a dark, resinous color containing an undetermined organic material. “Typically as isolated crystals, with {011} elongated along [010], terminated b {001}, to 4 cm; commonly corroded.2 A small hand specimen at the Friends of Mineralogy symposium at Kelso, Washington in 2003 in one of the display cases that had a small vug containing a radiating spray of tan needle like crystals up to about a cm.

Good specimens of weddellite from this locality are rare and an educated guess is that there may be less than 100 of them produced over the years the quarry was active. The number may be as few as a dozen or two. It is or was found in gas pockets within jasper. Organic material in the sediment in a shallow lake decomposed, giving off methane gas that created bubbles in the sediment. Some tiny rhombic appearing mineral formed in the bottom part of the cavity followed by quartz crystals. Most of the rhombic material has been dissolved out leaving salt-sized holes. Weddellite formed on top of the quartz crystals that lined the cavities and cemented the sediment into chert or jasper. The area is famous in the rockhound community for the attractively banded jasper that is found here. There are about 20 localities where it is found and it is known to the lapidary/rockhound crowd as Biggs Jasper. A fine specimen of the jasper can bring hundreds of dollars. The jasper from the Fulton Canyon quarry did not have as good a pattern as some of the other localities, but so far, the Fulton Canyon quarry is the only one where weddellite crystals have been found. Most of the weddellite was found while they were working this quarry for jasper in the 1980's. There never were very many specimens. Nobel Witt had the best and most. A 1 inch crystal is exceptional. There is only one specimen in the Rice Museum in Hillsboro, Oregon. Nobel Witt was the man who collected most of the specimens and is listed as a co-author on the Canadian Mineralogist article about the mineral. He died more than ten years ago and part of his collection was donated to the Seattle University. Some references state that the locality was flooded by the Dalles Dam, but this is not correct. The quarry that produces the weddellite is high and dry. The jasper bed in the Fulton Canyon quarry is situated between two Columbia River Basalt flows that are about 15 million years old. Isami (Sammi) Tsubota is the owner/operator of the quarry and is 93 years old and does not get around much anymore. The quarry is inactive but has "No Trespassing" signs and the locals sometimes shoot first and ask questions later if they find anyone on their land.
[Rock Currier & Rudy Tschernich (curator Rice Museum, Hillsboro, Oregon 7November 08]



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Edited 27 time(s). Last edit at 03/26/2012 06:55PM by Rock Currier.
Re: Weddellite
November 06, 2008 01:35PM
Rock, I don't know anything about the "Sami Tsubota jasper mine" - Is this really a "mine"? I'd heard these weddelites came from jasper nodules raked up from the seabed below low tide line.
avatar Re: Weddellite
November 06, 2008 07:37PM
I don't know anything about it either. That was the locality given by Bideaux. The jasper mine thing sounded a little strange to me too. This is exactly the kind of thing I hope to get corrected? or at least learn more about and described better, perhaps by some FM guys in the NW Chapter when this board goes out to the general mindat community. Meanwhile Ill see what I can find out.

Rock Currier
Crystals not pistols.
avatar Re: Weddellite
November 08, 2008 10:02AM
OK, the weddellite article is much better now. I contacted Bart Cannon in Washington and eventually ran down Rudy Tschernich of the Rice museum and he knew a lot about the locality.

Rock Currier
Crystals not pistols.
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