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Sperrylite
Posted by Rock Currier
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Sperrylite May 15, 2009 06:15PM |
Click here to view Best Minerals S 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?
Below are some preliminary notes I have made about Sperrylite. This entry and thread has been made as a place holder for information that you will hopefully contribute about Sperrylite. It should be in no way be thought of as a claim I have staked out to write about this mineral, and in fact is an invitation for someone to step forward and create the article about this mineral. If you are so inclined and have questions about the format that such an article should have, go the The welcome topic at the top of the Best Minerals forum and read what has been posted there. Also take a look at some of the more mature articles that have already been written like Rhodochrosite, Adamite, Millerite etc. You will need also to pick out other images of Sperryllite that will go into the article.
Sperrylite
PtAs2 Cubic
Here will go general comments about Sperrylite specimens in general.
Dear Rob,
in your captions to your photos [www.mindat.org] and [www.mindat.org] some errors exist.
Yellow mineral of marix is chalcopyrite (+/- cubanite) and apparently don't contain any talnakhite at all. Talnachite is orange-brown, bronze mineral on fresh breaks, but for some hours it become pinkish -> lilac -> violet and some days (4-5) it begin transform into dark violet-brown. It never is yellow.
Chromite is known in Norilsk group deposits, but mainly as 0.n-0.0n mm grains. All visible by eye black octahedrons in Norilsk masive sulphide ores are magnetites. Cromspinelides from here may be visible only in polished sections under microscope. These localities connected with gabbro-norites (basaltic rocks) not with ultrabasic ones, where chromites are abundant.
By the way, in 1992 I saw block of ore ~40x20x7 cm size from unspecified mine of the Norilsk group, in which sperryllite skeletons were so large, that I was unable to cover some of them by my palm (it is 10x9 cm, according to the last measurements ). The block contained some kg of sperryllite. Unfortunately it was divided into ~40-50 specimens. And some of them I saw here on mindat - [www.mindat.org] for example.
This block contained a lot of paolovite and nigglyite inclusions in the chalcopyrite "matrix". So it contained also additional 200-300 g of PGM besides obvious sperryllite.
My Dad was a pack rat who loved bargains. After he died I sent a 30 m moving van ( "pantechnion" for you English!)packed tightly with Dad's treasures to auction and with the entire proceeds bought the large specimen, At the the time the chalco was quite purple and billed as Talnakhite. What amazed me was the parallel growth of the sperrylite crystals. There seemed nothing commensurate between the "talnakhite" lattice and the sperrylite lattice that could account for the sperrylite's parallel growth. I showed it to Dr. Godoviko (sp?) from the Fersman and asked him why the parallelism. He said he had never seen such good sperrylites as were currently marketed in the States and said he had no idea why the parallelism. I pressed him and he replied with a strong Russian accent." Probably there are little worms of sperrylite between the crystals." That surprised me so I took it to Bart Cannon's and used his abrasive blaster to further excavate the specimen. Sure enough he was right. There were bars of sperrylite that connected the crystals in a skeletal growth!!!. The blasting removed the deep purple colour of the "talnakhite". I thought the purple would come back, but after nearly a decade it photoed as you see it. So I conclude that the last step in preping these for market was a soak in whatever turns chalco into "bornite" as commonly sold in rock shops. Bart told me that the black octos had been probed for someone else who thought they might be Laurites. I thought Bart said they turned out to be chromites. I'll ask Bart about it, but I doubt that he'll remember. Bart is pretty good, but there may be a problem with the amount of Cr in the black octos. He would have been looking for Ru, but saw some Cr instead and so called it chromite??? (Not according to your observations given above!!!) Recently there was some discussion about real chromites. Arghh!!! I may be mis remembering myself as my Borneo "Laurite" octos probed as Chromite. That is more likely. The other Sperrylite came from Brad Van Scriver and I did nothing to it, so the purple remained. A little of the "talnakhite" broke away from this piece and all was purple, so the fractures must have been present when the piece was soaked. l did no analytic work on these pieces.
This is a good example of "the world's biggest or best" The world is a very big place!!! Although nothing larger escaped Russia that I ever saw or heard of, it is not too surprising that much larger skeletal pieces existed. Thanks so much for the info. It is a real shame that the piece was broken up for commercial purposes. Curetonizing is breaking up a large piece that you couldn't sell for more than a few hunded dollars into fifty or more pieces that you can sell for $50. each.Obviously the vandals didn't know what they had as they could have sold it for far more as a huge skeletal piece rather than bits and pieces for hundreds to thousands. I'll clean up the captions. Thanks again!!!
This is good info for the Best Stuff and we should report it there. Also these specimens are now at the Royal Ontario Museum and I would like your permission to copy these messages to them.
Rob Woodside
Dear Rob,
laurite isn't known in Norilsk group deposits because of it is typical mineral of ultrabasic associations - chromite, Os-Ir-Ru alloys, erlichmanite, IsoFePt and 4FePt... Besides that, the largest laurite xls, about which I sometimes heard, hadn't exceed 2 mm.
These black octahedrons from Norilsk sulphide ores always are STRONG magnetic. No cromite hasn't such strong and obvious magnetism. Besides that, mostly chromite is more lustrous/reflective than magnetite.
Kind regards,
Click here to view Best Minerals S and here for Best Minerals A to Z and here for Fast Navigation of completed Best Minerals articles.
Rock Currier
Crystals not pistols.
Edited 8 time(s). Last edit at 07/26/2010 11:33AM 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?
Below are some preliminary notes I have made about Sperrylite. This entry and thread has been made as a place holder for information that you will hopefully contribute about Sperrylite. It should be in no way be thought of as a claim I have staked out to write about this mineral, and in fact is an invitation for someone to step forward and create the article about this mineral. If you are so inclined and have questions about the format that such an article should have, go the The welcome topic at the top of the Best Minerals forum and read what has been posted there. Also take a look at some of the more mature articles that have already been written like Rhodochrosite, Adamite, Millerite etc. You will need also to pick out other images of Sperryllite that will go into the article.
Sperrylite
PtAs2 Cubic
 | |
| Sperrylite, Noril'sk, Taimyr Peninsula, Taymyrskiy Autonomous Okrug, Russia 4.1cm wide | © fabreminerals.com |
Here will go general comments about Sperrylite specimens in general.
Dear Rob,
in your captions to your photos [www.mindat.org] and [www.mindat.org] some errors exist.
Yellow mineral of marix is chalcopyrite (+/- cubanite) and apparently don't contain any talnakhite at all. Talnachite is orange-brown, bronze mineral on fresh breaks, but for some hours it become pinkish -> lilac -> violet and some days (4-5) it begin transform into dark violet-brown. It never is yellow.
Chromite is known in Norilsk group deposits, but mainly as 0.n-0.0n mm grains. All visible by eye black octahedrons in Norilsk masive sulphide ores are magnetites. Cromspinelides from here may be visible only in polished sections under microscope. These localities connected with gabbro-norites (basaltic rocks) not with ultrabasic ones, where chromites are abundant.
By the way, in 1992 I saw block of ore ~40x20x7 cm size from unspecified mine of the Norilsk group, in which sperryllite skeletons were so large, that I was unable to cover some of them by my palm (it is 10x9 cm, according to the last measurements ). The block contained some kg of sperryllite. Unfortunately it was divided into ~40-50 specimens. And some of them I saw here on mindat - [www.mindat.org] for example.
This block contained a lot of paolovite and nigglyite inclusions in the chalcopyrite "matrix". So it contained also additional 200-300 g of PGM besides obvious sperryllite.
My Dad was a pack rat who loved bargains. After he died I sent a 30 m moving van ( "pantechnion" for you English!)packed tightly with Dad's treasures to auction and with the entire proceeds bought the large specimen, At the the time the chalco was quite purple and billed as Talnakhite. What amazed me was the parallel growth of the sperrylite crystals. There seemed nothing commensurate between the "talnakhite" lattice and the sperrylite lattice that could account for the sperrylite's parallel growth. I showed it to Dr. Godoviko (sp?) from the Fersman and asked him why the parallelism. He said he had never seen such good sperrylites as were currently marketed in the States and said he had no idea why the parallelism. I pressed him and he replied with a strong Russian accent." Probably there are little worms of sperrylite between the crystals." That surprised me so I took it to Bart Cannon's and used his abrasive blaster to further excavate the specimen. Sure enough he was right. There were bars of sperrylite that connected the crystals in a skeletal growth!!!. The blasting removed the deep purple colour of the "talnakhite". I thought the purple would come back, but after nearly a decade it photoed as you see it. So I conclude that the last step in preping these for market was a soak in whatever turns chalco into "bornite" as commonly sold in rock shops. Bart told me that the black octos had been probed for someone else who thought they might be Laurites. I thought Bart said they turned out to be chromites. I'll ask Bart about it, but I doubt that he'll remember. Bart is pretty good, but there may be a problem with the amount of Cr in the black octos. He would have been looking for Ru, but saw some Cr instead and so called it chromite??? (Not according to your observations given above!!!) Recently there was some discussion about real chromites. Arghh!!! I may be mis remembering myself as my Borneo "Laurite" octos probed as Chromite. That is more likely. The other Sperrylite came from Brad Van Scriver and I did nothing to it, so the purple remained. A little of the "talnakhite" broke away from this piece and all was purple, so the fractures must have been present when the piece was soaked. l did no analytic work on these pieces.
This is a good example of "the world's biggest or best" The world is a very big place!!! Although nothing larger escaped Russia that I ever saw or heard of, it is not too surprising that much larger skeletal pieces existed. Thanks so much for the info. It is a real shame that the piece was broken up for commercial purposes. Curetonizing is breaking up a large piece that you couldn't sell for more than a few hunded dollars into fifty or more pieces that you can sell for $50. each.Obviously the vandals didn't know what they had as they could have sold it for far more as a huge skeletal piece rather than bits and pieces for hundreds to thousands. I'll clean up the captions. Thanks again!!!
This is good info for the Best Stuff and we should report it there. Also these specimens are now at the Royal Ontario Museum and I would like your permission to copy these messages to them.
Rob Woodside
Dear Rob,
laurite isn't known in Norilsk group deposits because of it is typical mineral of ultrabasic associations - chromite, Os-Ir-Ru alloys, erlichmanite, IsoFePt and 4FePt... Besides that, the largest laurite xls, about which I sometimes heard, hadn't exceed 2 mm.
These black octahedrons from Norilsk sulphide ores always are STRONG magnetic. No cromite hasn't such strong and obvious magnetism. Besides that, mostly chromite is more lustrous/reflective than magnetite.
Kind regards,
Click here to view Best Minerals S and here for Best Minerals A to Z and here for Fast Navigation of completed Best Minerals articles.
Rock Currier
Crystals not pistols.
Edited 8 time(s). Last edit at 07/26/2010 11:33AM by Rock Currier.
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Re: Sperryllite May 21, 2009 04:59PM |
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Re: Sperrylite June 12, 2009 10:23AM |
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