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Kernite

Posted by Rock Currier  
avatar Kernite
July 01, 2009 09:05AM
Click here to view Best Minerals K and here for Best Minerals A to Z and here for Fast Navigation of completed Best Minerals articles.


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?



Kernite
Na2[B4O6(OH)2] ยท 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]



Click here to view Best Minerals K and here for Best Minerals A to Z and here for Fast Navigation of completed Best Minerals articles.

Rock Currier
Crystals not pistols.



Edited 5 time(s). Last edit at 07/26/2010 09:31AM by Rock Currier.
avatar Re: Kernite
July 02, 2009 10:35AM
The first draft of the Best Minerals Kernite article is finished.

Rock Currier
Crystals not pistols.
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