http://www.mindat.org/msgboard-77.html Sun, 29 Nov 2009 17:47:58 +0000 Phorum 5.2.8-RC1 http://www.mindat.org/forum.php?read,77,143465,143591#msg-143591 http://www.mindat.org/forum.php?read,77,143465,143591#msg-143591 Rock Currier Best Minerals K Thu, 02 Jul 2009 10:35:20 +0000 http://www.mindat.org/forum.php?read,77,143465,143465#msg-143465 http://www.mindat.org/forum.php?read,77,143465,143465#msg-143465


Kernite
Na₂[B₄O₆(OH)₂] · 3H₂O Omonoclinic

1. Kernite, 12cm wide	©

Kernite occurs in crystals (are you ready for this?) in crystals up to 3.5 meters in length although it is not usually a mineral you would want to put in your collection because under normal atmospheric conditions it will eventually end up, after a few years, as a pile of white powder in your specimen drawers unless you seal it up in a bottle and keep it in a cool dry place. It was discovered in 1925 during a drilling program by the United States Borax Company in the Mojave Desert. This locality originally known as the Kramer District is today know as Boron, California, the name of the little town that developed after mining of the deposit began. Usually new minerals are found only in small quantities and here was one that occurred in a masses of large intergrown crystals in a deposit 30 meters thick.¹ The mineral was known as rasorite till it was given the name Kernite by Schaller in 1927. It is found in the lower part of the borate ore body below the thick beds of Borax and apparently is the result of a low grade metamorphic process where the Borax looses some water and forms Kernite. In 1948 a second locality for Kernite was found at Tincalayu, Argentina. The crystals though not nearly as large and the deposit not so extensive, it is similar to the Kernite found at Boron. Even today, there are less than a half dozen known localities. In some circles that might qualify it as a rare mineral, except that where it is found, there are thousands of tons of it. The borate deposit at Kirka in Turkey also has a substantial content of the sodium borates of Borax and Kernite.²
1. Palache, C., H. Berman, and C. Frondell (1951) Dana's System of Mineralogy, (7th edition), v.II, 335-337. 2. Cahit Helvaci & Ricardo N. Alonso. Borate Deposits of Turkey & Argentina: A Summary and Geological Comparison. Turkish Journal of Earth Sciences, Vol.9, pp1-27.
[Rock Currier 2009]


Kernite
USA
California, Kern Co., Kramer District, Boron, U.S. Borax Open Pit Mine

2.Kernite, 14.5cm wide	©

3.Kernite,11cm wide	© 2008 Jesse Crawford

4.Kernite, 4cm across	© Peter Haas

More than 30 crystal forms of Kernite are known¹ but I wonder where in the world they found the crystals to measure. The only well developed crystals of Kernite I have seen have been from the giant dissolving tanks in the borate refinery at Boron and I suspect that the Kernite crystal pictured #4 above may be one of these. Periodically these big million gallon + tanks needs to be opened for clean out and maintenance. They break down the side of these big round concrete tanks so they can drive a bulldozer inside to clean things out and Kernite and Tincalconite crystals are found growing on the blades and walls of the tank. Perhaps when Palache, Berman and Frondel studied and described Kernite they had at their disposal crystals from the deposit that I have never seen, but let me assure you that if these crystals still exist (they may have hydrated to Tincalconite and fallen apart) they are rare creatures indeed. Given the size of the Kernite deposit at Boron, there are undoubtedly places where if you carefully washed the mud off the Kernite, crystal faces might indeed be found. But neither I or Jim Minette who was mine manager (both mineral collecting fiends) had any of these in our collections. As far as I know all the Kernite found at Boron is found at the bottom of the deposit where under the pressure of overlying rocks and perhaps modest heat, it lost some of its water and was altered to big intergrown lath like masses of Kernite. Kernite has sometimes been processed as ore, but it is not easy to process because of its perfect cleavage it does not break up nicely in small chunks, but forms nasty masses of splinters that have a habit of screwing up processing machinery. Some processing has been done by placing it in large piles and sprinkling it periodically with water. This allows the natural process of hydration ultimately into Tincalconite and the solution draining from the pile is rich in sodium borate and this can be readily processed into various borate compounds. At Boron, the company has built a nice little museum/visitor center overlooking the large open pit mine, and they periodically dump a truck load or two of ore from the deposit for visitors to pick through and haul off. Many times it consists of Kernite which when it is fresh looks great because it is fairly transparent to translucent and makes good specimens. See pictures 1,2 & 3 above. Tons of these specimens have been hauled away from the mine only to later gradually morph into mounds of white powder.

1. Palache, C., H. Berman, and C. Frondell (1951) Dana's System of Mineralogy, (7th edition), v.II, 335-337.
[Rock Currier 2009]]]> Rock Currier Best Minerals K Wed, 01 Jul 2009 09:05:06 +0000 http://www.mindat.org/forum.php?read,77,143453,143459#msg-143459 http://www.mindat.org/forum.php?read,77,143453,143459#msg-143459 Rock Currier Best Minerals K Wed, 01 Jul 2009 03:56:38 +0000 http://www.mindat.org/forum.php?read,77,143453,143453#msg-143453 http://www.mindat.org/forum.php?read,77,143453,143453#msg-143453


Kurnakovite
Mg(H₄B₃O₇)(OH) · 5H₂O triclinic

1.Kurnakovite & Ulexite,~11cm wide	©

Kurnakovite is a relatively rare borate mineral and is found at fewer than 10 localities thus far. It is dimoprhous with Inderite. Crystals of more than 30 cm have been found, and crystal clusters can exceed 50 cm. These well crystallized specimens are exclusively from the borate deposit at Boron, California and the specimens found at other localities are poor second cousins. The mineral was first described by the Russians from the Inder deposit in Kazakhstan.
[Rock Currier 2009]


Kurnakovite
Kazakhstan
Atyrau Oblysy (Atyrau Oblast'), Atyrau (Gur'yev), Inder B deposit and salt dome

2.Kurnakovite, 2.8cm wide	© Peter Kohorst

From the single picture we have of a specimen from Kazakhstan, the material looks to be earthy and massive. We need someone to tell us about the borates from the Inder locality in Kazakhstan.


Kurnakovite
USA
California, Kern Co., Kramer District, Boron, U.S. Borax Open Pit Mine

3.Kurnakovite, ~7cm diameter	©

4.Kurnakovite crystals.	© Caltech

5.Kurnakovite ~3cm tall	©

6.Kurnakovite ~12 cm tall	© Rob Lavinsky

The Kurnakovite crystals from the borate deposit at Boron, were almost all found during the early days of the open pit mine when they switched over from underground to open cast. They were found in a fault zone near the west end of the deposit. Many of the Kurnakovite crystals were found growing in the distinctively colored blue/gray/tan mud of the deposit and almost always associated with little intergrown fibrous knobs of Ulexite that are commonly stained to a greater or lesser extent by the mud from the deposit. When these were encountered hundreds of crystals were collected. Even ten years after the fact I was able to buy more than 100 crystals in a bag from a miner that had never been cleaned. Sometimes the crystals of Kurnakovite were more than a foot in diameter and clusters of these crystals of more than a half meter are known. The crystals for the most part are blocky with some few being tabular. Very rarely they were associated with Inderite crystals. Some pocket material with free standing crystals were found, but these pockets were never very big. Since the original discovery, in the 50s, no more specimens of Kurnakovite have been made. When specimens of Kurnakovite are transported from the dry clean desert air of the Boron area, down into the polluted air of Los Angels, it is typical for the specimen to develop a white coating starting on the edges of the crystals and then white spots appear on the crystal faces and finally a thin white coating will develop to coat the entire specimen like seen in picture #3. The crystals that remain in the clean dry air of Boron are rarely affected with this problem. It is commonly ascribed to a dehydration process, but I believe that in the polluted air of big cities that the Kurnakovite is reacting with some of the containments in the air. This coating can be largely removed by soaking the specimen briefly in water. Other than this, Kurnakovite and Inderite are stable and do not fall apart like the sodium borate minerals found at Boron. These large crystals of Kurnakovite are quite heat sensitive and if you put in in water that is warmer or colder than the crystal, you will crack it. Take it from one who has done just that. Probably fewer than 1000 specimens of all kinds were collected.
[Rock Currier 2009]]]> Rock Currier Best Minerals K Wed, 01 Jul 2009 02:57:52 +0000 http://www.mindat.org/forum.php?read,77,139665,140395#msg-140395 http://www.mindat.org/forum.php?read,77,139665,140395#msg-140395
Paul.]]> Paul De Bondt Best Minerals K Thu, 04 Jun 2009 08:30:44 +0000 http://www.mindat.org/forum.php?read,77,139665,139667#msg-139667 http://www.mindat.org/forum.php?read,77,139665,139667#msg-139667 Rock Currier Best Minerals K Thu, 28 May 2009 18:47:47 +0000 http://www.mindat.org/forum.php?read,77,139665,139665#msg-139665 http://www.mindat.org/forum.php?read,77,139665,139665#msg-139665

Kamotoite-(Y)
Y₂(UO₂)₄[O₄|(CO₃)3] · 14H2O Monoclinic

Kamotoite-(Y), Kamoto East Open cut, Kolwezi, Katanga DR Congo 16.4cm wide	© Paul De Bondt

Kamotoite-(Y)
Congo, Democratic Republic of
Katanga (Shaba), Katanga Copper Crescent, Western area, Kolwezi, Kamoto, Kamoto East Open cut

Kamotoite-(Y) FOV 5mm	© Thomas Witzke

Kamotoite-(Y) & others 5.8cm wide	© Rob Lavinsky

The pictured specimen is the best specimen known and comes from the personal collection of J.M. Pendeville, who discovered the pocket and is now in my collection. The second best specimen is in the Sorbonne, Paris, collection. The third best is also in my personal collection. The specie is not rare at the deposit but good crystallized specimens are very rare and only less than 5 are top grade. Most specimens are crystalline masses or coatings. The mineral sit on unaltered massive Uraninite and is VERY radioactive. The Uraninite from Shinkolobwe is around 656 milion years old ( Dr. Michel Deliens ) The Uraninite from Kamoto must be younger because for the same quantity, the radiation is much higher.

Kamotoite was discovered in the early 1980’s by the late Jean-Marie Pendeville in the Kamoto East open cut, situated near the city of Kolwezi, Western area of the Katanga Copper Belt in the Democratic Republic of the Congo. The formal description was done in 1986 by M. Deliens et P. Piret. Kamotoite is a hydrated Carbonate of Uranyl and Rare Earths. The REE are in declining order of importance, Y, Nd, Gd, Sm and Dy. It is the most important mineral that was found in a Uranium-bearing pocket associated with Shabaite-(Nd), Astrocyanite-(Ce), Schuilingite-(Nd) and Uranophane. A little Curite is also present. The mineral has a very attractive lemon to golden yellow colour and forms rarely radiated structures.
The crystals are monoclinic and are terminated in a point forming an angle of 35 °. As of 2009 only 5 occurrences are known and Kamoto East is the most important.
[Paul De Bondt 2009]

Perhaps we should include a description of Kamotoite-(Y) from other localities here, but we need someone to tell us about them and to upload pictures of them. I have a feeling that compared to the specimen pictured above, they would all be at least two orders of magnitude less quality, probably barely yellow stains on rock. Does anyone have information to the contrary? Actually I am pretty sure that some decent micro crystals have been found at some of these other localities, but am trying to goad some of the people who specialize in minerals from those areas to step up and help us make this a better article.]]> Rock Currier Best Minerals K Thu, 28 May 2009 18:39:55 +0000 http://www.mindat.org/forum.php?read,77,129403,139619#msg-139619 http://www.mindat.org/forum.php?read,77,129403,139619#msg-139619
It looks like you are almost done with the letter A. Tremendous job.
To follow the alphabetic logic of the topic I will contribute with a K mineral.(:P)

Here it is :

Kamotoite was discovered in the early 1980’s by the late Jean-Marie Pendeville in the Kamoto East open cut, situated near the city of Kolwezi, Western area of the Katanga Copper Belt in the Democratic Republic of the Congo.
The final description was made in 1986 by M. Deliens et P. Piret.

Kamotoite is a hydrated Carbonate of Uranyl and Rare Earths. The REE are in declining order of importance, Y, Nd, Gd, Sm and Dy. It is the most important mineral that was found in a Uranium-bearing pocket associated with Shabaite-(Nd), Astrocyanite-(Ce), Schuilingite-(Nd) and Uranophane. A little Curite is also present.

The mineral has a very attractive lemon to golden yellow colour and forms rarely radiated structures.
The crystals are monoclinic and are terminated in a point forming an angle of 35 °.
The specie is not rare at the deposit but good crystallized specimens are very rare and only less than 5 are top grade. Most specimens are crystalline masses or coatings. The mineral sit on unaltered massive Uraninite and is VERY radioactive. The Uraninite from Shinkolobwe is around 656 milion years old ( Dr. Michel Deliens ) The Uraninite from Kamoto must be younger because for the same quantity, the radiation is much higher. I will ask Dr. Deliens if he could tell us how “ young “ the Uraninite from Kamoto is.
The pictured specimen is the best specimen known and comes from the personal collection of J.M. Pendeville, who discovered the pocket and is now in my collection. The second best specimen is in the Sorbonne, Paris, collection. The third best is also in my personal collection.

Until today, ( may 2009 ), only 5 occurrences are known and Kamoto East is the most important.

[www.mindat.org]

I hope this helps.

Take care and best regards.

Paul.]]> Paul De Bondt Best Minerals K Thu, 28 May 2009 13:05:02 +0000 http://www.mindat.org/forum.php?read,77,129403,129403#msg-129403 http://www.mindat.org/forum.php?read,77,129403,129403#msg-129403
Ideally what we want to know about each significant mineral from each locality is:

1. What is the largest crystal of the mineral that the locality has produced?
2. What do the best specimens from this locality look like and where can one be seen?
3. Does the locality produce a variety of different kinds of specimens of this species, and what do the best of each type look like and how many of them were found etc.
4. What are the associated minerals found with this species and what is its geological setting?
5. How abundant are these specimens and when were they found? A type locality? In other words, how rare are they.
6. How do they compare to other specimens of the same mineral from other localities?
7. How much is it worth. This should probably be optional, but in cases where specimens are worth thousands of dollars we should probably say something of the value of these things.
8. What kind of care and feeding do these specimens require? Are they delicate, radioactive, unstable, color changeable etc.?
9. Are the specimens commonly faked, and if so, how to tell if they are?
10. Are there any interesting stories relating to the collecting of these specimens or their discovery as a new mineral?

Of course this is in reality impractical, but if we keep these questions in mind, we will do a lot better job when writing about them.]]> Rock Currier Best Minerals K Fri, 06 Mar 2009 11:18:48 +0000