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NOTES RE: Uraninite replacing wood

Many of the uranium-rich ore deposits in the central USA consist of sedimentary formations in which downed logs from ancient forests created an environment favorable to the deposition of ores as replacements of the very ancient wood and other plant materials by Uraninite, as well as by numerous secondary uranium and vanadium minerals.  These deposits are localized within the area known as the Colorado Plateau, which includes portions of the states of Colorado, Utah, Arizona and New Mexico, as well as parts of Wyoming.  Small amounts of Pyrite and / or Chalcopyrite are sometimes associated in these uranium-rich ore deposits, along with other sulfides.  In some areas Bornite and Chalcocite are also present, indicating a greater enrichment of Copper in the deposits.  Of course, these are no longer forested areas at the present time and, in many places, these localities are now practically considered to be desert-like in nature.  These uranium-rich sedimentary deposits are chiefly made up of conglomerates and / or sandstones.  Geologically, this is very different from localities like Jachymov and Joachimsthal in Czechoslovakia, Katanga, Zaire, and the Great Bear Lake area in the NWT, Canada, where the Uraninite was formed in hydrothermal veins.  It is only by luck or good fortune that we have any specimens surviving in collections from the “Uranium rush” era of the 1950’s to early 1960’s.  During that period, the United States government encouraged mining for Uranium ores and everything was processed in the name of the “arms race”, i.e., at the time of the cold war with Russia.  Unfortunately, the Russians were doing the same at Jachymov and other Central European localities, to get ready for a possible war with the USA.  Untold numbers of fine examples of Uraninite and other uranium-bearing ore minerals from both countries were undoubtedly destroyed in the course of processing the ores from these uranium-rich deposits for defense purposes.  All of the specimens described below are from the Eugene B. Gross collection.  Dr. Gross worked for the AEC during the late 1950’s to early 1960’s and was personally responsible for collecting these historically important specimens, and preserving them in his private collection



= Fluorescent Specimen
   =  Radioactive Specimen

mi1084a.jpg (41162 bytes)
A.
mi1084b.jpg (31568 bytes)
B.

URANINITE and PYRITE replacing wood
Continental Uranium Mine, Powder River Basin, Wyoming
Superb examples of Uraninite and Pyrite replacing wood! Radioactivity is very high on both specimens.

MI-1084-A   This is nearly a quarter section of a complete log which has been sawed.  That is, it is a V shaped section of a complete log that was probably about 6 1/2" in diameter.  The slice is 1 1/4" thick.  It has been polished on the front surface and has an epoxy coating on the sides and back of the slice.  The Uraninite is shiny black and very dense, and the Pyrite is shiny metallic golden color, as rich veinlets and swirls within the Uraninite. A small amount of Chalcopyrite is also present. Beautiful! 
Specimen size:  3 1/4" from the top of the V to the base of the V, 3 3/4" wide across the top of the V, and 1 1/4" thick
Gram weight:  642.90 grams
> 50 mR/hr @ 1”, with CD V-700
> 30,000 CPM @ 1”, with CD V-700
Price: 
SOLD , less 10% quantity discount = net price of $376.00  (A 10% quantity discount is given on all Uraninite specimens in our inventory
that are 500 grams and larger.)

MI-1084-B  A smaller example, possibly from the same log as the specimen described above, with very dense black Uraninite replacing wood, associated with metallic golden color Pyrite and a very minor amount of Chalcopyrite.  This nicely prepared specimen has the top surface polished (cut across the grain of the wood), while the sides and base of the specimen are in natural condition.
Specimen size:  1 7/8” X 1 1/8” across the cut surface, X 2” tall.
Gram weight:  270.00 grams
> 50 mR/hr @ 1”, with CD V-700
> 30,000 CPM @ 1”, with CD V-700
Price: 
SOLD

mi1085.jpg (56852 bytes)

URANINITE replacing wood
La Sal #2 Mine, Big Indian Wash, San Juan Co., Utah
This specimen looks like a piece of wood!  This V shaped specimen is about 1/8 of a slice of a log that was originally approximately 5 1/2" to 6" in diameter.  The center of the log is mostly replaced by Uraninite, while the outer portion is replaced by rock. The rock is a light brick red color -- it is from the deposit that was called "red logs" because of the color -- it is not bright red, but you can see that it is a nice light brick red color, in contrast to the black color of the Uraninite.  You can easily see the curved structure of the wood -- this looks like a piece of ordinary petrified wood, yet the center is replaced by Uraninite.
Order Item  MI-1085
Specimen size:  3" thick, 2 1/4" wide at the top of the V, and nearly 3" across from the top of the V to the base of the V.
Gram weight:  496.50 grams
5 mR/hr @ 1”, with CD V-700
3,000 CPM @ 1”, with CD V-700
Price:  $173.75, less 10% quantity discount = net price of $156.25  (A 10% quantity discount is given on all Uraninite specimens in our inventory that are 500 grams and larger.) 
SOLD

URANINITE , PYRITE and QUARTZ replacing wood
“C” Group, Inter-River / Green River Area, Emery County, Utah
This interesting section of a small tree trunk or limb has had the front of the specimen cut and polished.  On the cut surface, one can see the growth rings of the wood alternately replaced by black Uraninite, plus a mixture of Quartz and Pyrite.  A mixture of granular Quartz and Pyrite surround the Uraninite replacement after wood on the right side of the specimen, as oriented in the photograph.  Small amounts of Chalcopyrite and Bornite are also present.  A secondary deposition of yellow-green Schrockingerite coats portions of the perimeter of the specimen. Schrockingerite is a hydrous fluor-carbonate-sulfate of Na, Ca, and UO, and is fluorescent bright greenish-yellow under both SW and LW UV.  From the Dr. Eugene B. Gross collection.
Specimen weight:  68.05 grams
Specimen size:  2” X 1 1/8” across, X up to 7/8” thick
10 mR/hr @ 1” with CD V-700
7,500 CPM @ 1” with CD V-700Order Item MI-1116             
Price:  $40.00 
SOLD

 

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