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Tincalconite
Posted by Rock Currier
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Tincalconite June 30, 2009 06:07AM |
Click here to view Best Minerals T 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?
Tincalconite
Na2B4O7 ยท 5H2O trigonal
Almost all Tincalconite specimens are pseudomorphs after Borax. They are water soluble. They are almost all a uniform opaque white color and if kept in conditions of fluctuating temperature and humidity have a nasty habit of ending up as piles of white powder. Some of the specimens, especially the ones from Boron, California make striking specimens, but will degrade unless cared for rigorously. Individual specimens to 30 cm are known, but these are very prone to cracking as the Borax dehydrates. Tincalconite crystals or rather their pseudomorphs after Borax are found where ever Borax crystallizes. Almost all the specimens that are in collections today are from altered Borax specimens that have been collected from the sumps and the bottoms of flooded stopes in the old underground mine at Boron. Some would argue that they are not real minerals because man had a hand in creating them and would not have formed at all except in artificial pools and ponds created by man. Some primary crystals of Tincalconite are known but those that I know of grew as somewhat elevated temperatures in the giant solution tanks at the borate refinery at Boron, California. About the only way to preserve these specimens is to keep them in a cool dry place that is free from humidity and temperature fluctuation and in some some sort of container to prevent dust, and exposure to atmospheric containments. In practical terms, that means that most storage facilities, institutional and private, can not care properly for these specimens.
[Rock Currier 2009]
Tincalconite
China
Tibet Autonomous Region
These old specimens are in the collection of the British Museum of Natural history, are very fragile and show signs of falling apart because of partial rehydration and drying over the years. I am surprised that they have lasted as long as they have. When Borax is freshly altered to Tincalconite, the crystals are quite sharp like in picture one. After some years of alternating hydration and drying the crystals get a "puffy" look like we see in these Tibetan crystals in picture 2 above. We need someone to tell us about the Borax and Tincalconite production from Tibet.
[Rock Currier 2009]
Tincalconite
USA
California, Kern Co., Kramer District, Boron, U.S. Borax Open Pit Mine
Most of the Tincalconite specimens from Boron have their origin as clusters of Borax crystals that have been collected from sumps and partially flooded stopes from the old underground mine. Most of them have been collected from the West Baker mine because for years it was possible to drive a vehicle through the big tunnels right to the partially flooded stopes where the collecting was done. This I think is still possible. At one time it used to be possible to drive from the West Baker mine over to the Baker mine which accessed the eastern part of the borate deposit, but I think that some breakdown from caving has closed this to vehicles. The specimen #1 is from the West Baker section of the mine and number four is from a sump in the older Baker mine. I am not sure exactly where the other Boron specimen are from exactly. At any rate, they are all from the old underground section of the mine which is no longer operated and not from the big new open pit mine that is now mined exclusively for ore. When the specimens are fresh, very white and sharp they can make spectacular specimens. Some have been traded with museums for very valuable specimens to curators who were not aware that these fine looking specimens would in years to come get dirty and subject to rehydration. Being water soluble you of course can not clean them with water. The "primary" Tincalconite in picture #6 was taken from one of the giant dissolving tanks in the refinery during one of their infrequent "clean outs" when they break open the side of these big round concrete structures so they can drive a bulldozer inside to clean things out. Primary Tincalconite and Kernite crystals have been found growing on the big rotating mixing blades and the walls of the tanks.
[Rock Currier 2009]
Tincalconite
USA
California San Bernardino Co., Searles Lake
Searles Lake is a dry lake of some depth and is really nothing more than a big mash of brine and crystals of various water soluble minerals. Some of them are unique to the lake. Almost all of them are unstable to some degree and require special methods to keep them intact. A lot of halite (salt) crystals have been collected from ponds and trenches created by old mining projects in the lake bed but most of the other minerals are produced from bore holes down through the lake (crystal mash) and taken from drill cores or more commonly boosted to the surface by air bubbles that raft the crystals up to the surface where they spill out onto the hardened dry salt surface. Once a year, at the time of the local gem and mineral show the mining company that mines the lake for various chemicals lead field trips for collectors out onto the surface of the lake. They drop an explosive charge to the bottom of some of their bore holes (wells) and use air to raft the broken up crystal mash to the surface where collectors wait to pounce on them and load as many kilograms as possible into their cars, which they can drive right up to the collecting sites. The specimen of Hanksite pictured above was undoubtedly collected at one of these annual field trips. However, when the specimen was collected, the Tincalconite that is perched on the doubly terminated Hanksite was undoubtedly a relatively sharp, transparent Borax crystal which has since altered to Tincalconite and because of subsequent intermittent rehydration and drying started to loose its sharp crystal outline and get "puffy".
[Rock Currier 2009]
Click here to view Best Minerals T and here for Best Minerals A to Z and here for Fast Navigation of completed Best Minerals articles.
Rock Currier
Crystals not pistols.
Edited 14 time(s). Last edit at 03/26/2012 06:44PM by Rock Currier.
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?
Tincalconite
Na2B4O7 ยท 5H2O trigonal
Almost all Tincalconite specimens are pseudomorphs after Borax. They are water soluble. They are almost all a uniform opaque white color and if kept in conditions of fluctuating temperature and humidity have a nasty habit of ending up as piles of white powder. Some of the specimens, especially the ones from Boron, California make striking specimens, but will degrade unless cared for rigorously. Individual specimens to 30 cm are known, but these are very prone to cracking as the Borax dehydrates. Tincalconite crystals or rather their pseudomorphs after Borax are found where ever Borax crystallizes. Almost all the specimens that are in collections today are from altered Borax specimens that have been collected from the sumps and the bottoms of flooded stopes in the old underground mine at Boron. Some would argue that they are not real minerals because man had a hand in creating them and would not have formed at all except in artificial pools and ponds created by man. Some primary crystals of Tincalconite are known but those that I know of grew as somewhat elevated temperatures in the giant solution tanks at the borate refinery at Boron, California. About the only way to preserve these specimens is to keep them in a cool dry place that is free from humidity and temperature fluctuation and in some some sort of container to prevent dust, and exposure to atmospheric containments. In practical terms, that means that most storage facilities, institutional and private, can not care properly for these specimens.
[Rock Currier 2009]
Tincalconite
China
Tibet Autonomous Region
These old specimens are in the collection of the British Museum of Natural history, are very fragile and show signs of falling apart because of partial rehydration and drying over the years. I am surprised that they have lasted as long as they have. When Borax is freshly altered to Tincalconite, the crystals are quite sharp like in picture one. After some years of alternating hydration and drying the crystals get a "puffy" look like we see in these Tibetan crystals in picture 2 above. We need someone to tell us about the Borax and Tincalconite production from Tibet.
[Rock Currier 2009]
Tincalconite
USA
California, Kern Co., Kramer District, Boron, U.S. Borax Open Pit Mine
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| 4.Tincalconite altering from Borax ~7cm wide | © |
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| 6.Tincalconite ~5cm wide | © |
Most of the Tincalconite specimens from Boron have their origin as clusters of Borax crystals that have been collected from sumps and partially flooded stopes from the old underground mine. Most of them have been collected from the West Baker mine because for years it was possible to drive a vehicle through the big tunnels right to the partially flooded stopes where the collecting was done. This I think is still possible. At one time it used to be possible to drive from the West Baker mine over to the Baker mine which accessed the eastern part of the borate deposit, but I think that some breakdown from caving has closed this to vehicles. The specimen #1 is from the West Baker section of the mine and number four is from a sump in the older Baker mine. I am not sure exactly where the other Boron specimen are from exactly. At any rate, they are all from the old underground section of the mine which is no longer operated and not from the big new open pit mine that is now mined exclusively for ore. When the specimens are fresh, very white and sharp they can make spectacular specimens. Some have been traded with museums for very valuable specimens to curators who were not aware that these fine looking specimens would in years to come get dirty and subject to rehydration. Being water soluble you of course can not clean them with water. The "primary" Tincalconite in picture #6 was taken from one of the giant dissolving tanks in the refinery during one of their infrequent "clean outs" when they break open the side of these big round concrete structures so they can drive a bulldozer inside to clean things out. Primary Tincalconite and Kernite crystals have been found growing on the big rotating mixing blades and the walls of the tanks.
[Rock Currier 2009]
Tincalconite
USA
California San Bernardino Co., Searles Lake
 | |
| Tincalconite after Borax on Hankiste ~8cm wide | © Rob Lavinsky |
Searles Lake is a dry lake of some depth and is really nothing more than a big mash of brine and crystals of various water soluble minerals. Some of them are unique to the lake. Almost all of them are unstable to some degree and require special methods to keep them intact. A lot of halite (salt) crystals have been collected from ponds and trenches created by old mining projects in the lake bed but most of the other minerals are produced from bore holes down through the lake (crystal mash) and taken from drill cores or more commonly boosted to the surface by air bubbles that raft the crystals up to the surface where they spill out onto the hardened dry salt surface. Once a year, at the time of the local gem and mineral show the mining company that mines the lake for various chemicals lead field trips for collectors out onto the surface of the lake. They drop an explosive charge to the bottom of some of their bore holes (wells) and use air to raft the broken up crystal mash to the surface where collectors wait to pounce on them and load as many kilograms as possible into their cars, which they can drive right up to the collecting sites. The specimen of Hanksite pictured above was undoubtedly collected at one of these annual field trips. However, when the specimen was collected, the Tincalconite that is perched on the doubly terminated Hanksite was undoubtedly a relatively sharp, transparent Borax crystal which has since altered to Tincalconite and because of subsequent intermittent rehydration and drying started to loose its sharp crystal outline and get "puffy".
[Rock Currier 2009]
Click here to view Best Minerals T and here for Best Minerals A to Z and here for Fast Navigation of completed Best Minerals articles.
Rock Currier
Crystals not pistols.
Edited 14 time(s). Last edit at 03/26/2012 06:44PM by Rock Currier.
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Re: Tincalconite June 30, 2009 10:40AM |
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Locality Updated: Shin-Otani mine, Ukyou-ku, Kyoto Prefecture, Kinki Region, Honshu Island, JapanFrom Hiroaki Tano, 22nd May 2013 11:37:03