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nurbo
Joined: 23 Sep 2008
Posts: 457
Location: Lancashire
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Posted: Feb 18, 2012 06:17 Post subject: Re: Collection of Nurbo |
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Ive been trying to get a decent photo of this for a while, in a vug in the usual Ojuela limonitic matrix there is a tiny stalactite of dark green Conichalcite (or it could be Malachite or even Rosasite I guess, its hard to say without testing) on top of this is a tiny (2mm) hairy spray of lime green Conichalcite,
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Conichalcite Ojuela Mine, Mapimi, Durango, Mexico. Conichalcite spray 2 mm |
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32674 Time(s) |
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nurbo
Joined: 23 Sep 2008
Posts: 457
Location: Lancashire
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Posted: Mar 10, 2012 19:16 Post subject: Re: Collection of Nurbo |
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Hello,
A killer Witherite, with an interesting tale ... the given locality is under some measure of doubt, it was in a box of Haggs mine pieces but the collector I got it from and myself too think it looks more like a Settlingstones Mine piece, a search on Mindat reveals one piece from Haggs that looks similar from a very reputable UK collector whose localities are beyond doubt whereas it gives several Settlingstones pieces which look identical its certainly from one or the other but Ill leave it as Northern England unless I get proof either way.
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Witherite Northern England max dimension 10 cm |
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32536 Time(s) |
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nurbo
Joined: 23 Sep 2008
Posts: 457
Location: Lancashire
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Posted: Mar 23, 2012 18:25 Post subject: Re: Collection of Nurbo |
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A brief interaction on mindat seems to support the whole Settlingstones theorum, not that anyone seems bothered,. but these things are important, the North of England has ridiculously large deposits of Witherite, mostly massive stuff, much of which was used as Barium ore in Victorian times.
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nurbo
Joined: 23 Sep 2008
Posts: 457
Location: Lancashire
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Posted: Mar 28, 2012 17:37 Post subject: Re: Collection of Nurbo |
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So I got my Rogerley twin from the Greenbank days YAAAY!. Also a new addition to my collection of twins, Neptunite from the San Benito gem mine.
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Fluorite Rogerley Mine, Frosterley, Co Durham, England, UK 3 cm across in shade |
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Fluorite Rogerley Mine, Frosterley, Co Durham, England, UK 3 cm across in not shade |
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Neptunite San Benito Gem Mine, California, USA. 2cm across |
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John S. White
Site Admin
Joined: 04 Sep 2006
Posts: 1295
Location: Stewartstown, Pennsylvania, USA
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Posted: Mar 29, 2012 04:34 Post subject: Re: Collection of Nurbo |
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Most references describe neptunite as black and, indeed, untwinned crystals from the Benitoite mine are black. But for some reason, and according to John Veevaert, the twins are always heavily included by the mineral crossite so they have the odd color of this one shown by nurbo. Just to complicate matters, crossite was descredited in 1997 as either glaucophane or ferroglaucophane or magnesioriebeckite or riebeckite. Hope that is crystal clear!
_________________ John S. White
aka Rondinaire |
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nurbo
Joined: 23 Sep 2008
Posts: 457
Location: Lancashire
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Posted: Mar 31, 2012 02:14 Post subject: Re: Collection of Nurbo |
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Thanks for that John, I did wonder why the surface structure appears so chaotic it is now, as they say, as clear as mud..
I have another piece which Ive long suspected to be heavily included Neptunite, Ill publish the photo's I have and throw the question open to all observers. I know its almost impossible to be certain without the rock in hand but you never know someone out there might have seen something similar. It took me ages to clean the matrix off this piece, sort of a work in progress, though Ive had it in my collection for about 4 years.
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? Dallas Gem Mine, San Benito, California, USA approx 25 mm (max dimension) |
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JohnVeevaert
Joined: 14 Jul 2011
Posts: 5
Location: California
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Posted: Mar 31, 2012 10:33 Post subject: Re: Collection of Nurbo |
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I would say this ~could~ be a piece of neptunite that is included. It also has the appearance of heavily included piece of almandine too. The only way to be sure would be ramans or XRD analysis. But then one would ask why spend the $ on a fragment...? I know of only two specimens of twinned neptunite on Miller indices 301 that are not included with amphibole. 99.99% are included and look reddish. These twins are fairly common from the Benitoite Gem mine. Neptunite twinned on 001 is exceedingly rare with less than ten known specimens and they all are free of inclusions.
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nurbo
Joined: 23 Sep 2008
Posts: 457
Location: Lancashire
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Posted: Mar 31, 2012 17:17 Post subject: Re: Collection of Nurbo |
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Hello ,
Its an interesting piece, it has hundreds of terminal and prism faces on each side, I wouldnt call it a "Fragment" by any stretch of the imagination, my understanding of a "Fragment" is that its a piece broken off a larger sample and doesnt really have any defined crystal structure beyond fracture marks on most sides, this has very clearly defined defined crystal structure on every side, it is more like some kind of insane cluster than a fragment. I just had a poke around on Mindat and Almandine isnt listed from the Dallas Gem Mine so Ive nothing to compare it to. Do you have any photo's of these Almandines John? Id be interested to get a comparison.
Im interested to hear your opinion though,
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nurbo
Joined: 23 Sep 2008
Posts: 457
Location: Lancashire
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Posted: Mar 31, 2012 18:07 Post subject: Re: Collection of Nurbo |
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Heres a lovely Fluorite I recently got my hands on, unusual green Fluorite from West Pasture Mine.
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Fluorite, quartz West Pasture Mine, Stanhope, Weardale, Co Durham, UK. Fluorite to 11mm, specimen 47 x 44 mm |
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32236 Time(s) |
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JohnVeevaert
Joined: 14 Jul 2011
Posts: 5
Location: California
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Posted: Apr 01, 2012 08:23 Post subject: Re: Collection of Nurbo |
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First Almandine was never found at the Benitoite Gem mine. I was merely suggesting that the specimen may be almandine. What I see in your photos looks more like cleavage planes vs crystal faces. And they look a bit hackly which would fit in with almandine. Do you have locality info for this specimen? Neptunite is also harder than garnet so a hardness test might help you ID it. If it is neptunite it is not a crystal but merely a crystal fragment. Try a hardness test on it and report back.
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nurbo
Joined: 23 Sep 2008
Posts: 457
Location: Lancashire
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Posted: Apr 02, 2012 15:23 Post subject: Re: Collection of Nurbo |
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Hello again,
Outstanding micro crystals of Aragonite from the Heights Quarry.
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Aragonite Heights Quarry, Westgate, Weardale FOV 20 mm across. |
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nurbo
Joined: 23 Sep 2008
Posts: 457
Location: Lancashire
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Posted: Apr 03, 2012 14:57 Post subject: Re: Collection of Nurbo |
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Here is a cracking hexagonal Witherite being partially pseudomorphed by Baryte with Quartz and Sphalerite, obviously from the Haggs Mine, which is rapidly becoming a real favourite of mine.
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Witherite, Baryte, Sphalerite, Quartz. Haggs Mine, Nentsberry, Alston Moor, Cumbria, England, UK. 50 mm across |
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31990 Time(s) |
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nurbo
Joined: 23 Sep 2008
Posts: 457
Location: Lancashire
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Posted: Apr 06, 2012 14:14 Post subject: Re: Collection of Nurbo |
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So I bagged this piece recently in a trade, you can see the mine (with binoculars) from the end of my street. I would strongly suspect the inclusions to be one of the Manganese oxides that are fairly common inclusions in Calcite round here rather than "limonite/haematite" though Ill get some close ups and post them in due course.
https://www.johnbetts-fineminerals.com/jhbnyc/mineralmuseum/picshow.php?id=25244
Speaking of which here is a Calcite with what Is regarded as Pyrolusite from the Middlebarrow Quarry in Lancashire. I was going to trim it into three specimens but I think Ill leave it just as it is.
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Calcite with Pyrolusite(?) Middlebarrow Quarry, Silverdale, Lancashire. 19 cm across |
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Calcite with Pyrolusite(?) Middlebarrow Quarry, Silverdale, Lancashire. FOV approx 45 mm |
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Philip G
Joined: 13 Aug 2009
Posts: 54
Location: North Lancashire, England
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Posted: Apr 06, 2012 15:00 Post subject: Re: Collection of Nurbo |
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Hi David,
Yes ... there is a well defined bed of what is generally considered to be a manganese ironstone in Middlebarrow. Although the manganese oxides found within and on the calcites there are as yet untested, they have been given a basic visual identification of pyrolusite. As you know, the same limestone beds are also to be found on the other side of Morecambe Bay and very similar specimens containing manganese oxides can be found at many of the Lindal/Dalton iron mine sites also ... including, probably, the excellent Stank mine calcite you now own and refer to in the John Betts link.
Although Betts did say that it may be limonite or hematite included, with a little bit of local knowledge, I do believe you may well be correct in saying that it is more likely to be a manganese oxide but, of course, without specific testing we cannot say for sure exactly what it is. I have seen calcite specimens from Stank labelled with both pyrolusite and manganite being present ... plus, of course, the well known red inclusions and coatings of hematite.
Cheers.
Phil
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nurbo
Joined: 23 Sep 2008
Posts: 457
Location: Lancashire
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Posted: Apr 06, 2012 18:16 Post subject: Re: Collection of Nurbo |
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Hi Phil,
Your knowledge of the geology of this area is particularly outstanding, I wondered how far north do the Manganese oxide beds spread without interruption,given that the West Cumberland Iron ore fields end on the beach at Silverdale but stretch out into the atlantic and travel north beyond the reaches of the lake district, I wondered how big the Manganese deposite were, or if they were more just pockets where the concentration of Manganese is significant enough to form crystallisation.
cheers
db
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Philip G
Joined: 13 Aug 2009
Posts: 54
Location: North Lancashire, England
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Posted: Apr 07, 2012 07:24 Post subject: Re: Collection of Nurbo |
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Hi again,
Thanks David ... that is a big question to answer and way beyond the experience of this amateur mineral collector!
I presume that the Mn and Fe oxide deposits are regularly seen together in this region. As mentioned previously, the Park and Urswick limestone formations seen at Middlebarrow are found on both sides of the Bay and so, due to the relatively small distances involved, similar occurrences of both oxides in those formations but in differing amounts is probably to be expected.
Most of the major hematite deposits in South Cumbria seem to have been in the lowest Carboniferous limestone formations, named as Dalton, Red Hill Oolite and Martin, which occur immediately below the Park and Urswick.
I only have experience of surface mineral collecting in each of the areas and therefore can only relate to the very small amount of minerals seen and collected on dumps, tips etc. I do not know if the presence of some manganese ironstones were ever of great economical importance. Perhaps someone else could help to answer that question.
There are several very interesting BGS geological memoirs and reports on the mineral deposits and limestone formations of South Cumbria and North Lancashire to be found at the BGS website https://www.bgs.ac.uk/ and perhaps these will provide the answers to your questions. The whole question of the formation of the West and South Cumbrian metasomatic hematite deposits is apparently a quite complex one but it is covered in great detail within the geological memoirs suggested.
Also, for interest, refer to the BGS Mineral Reconnaissance Report PDF download at:
https://www.bgs.ac.uk/downloads/start.cfm?id=1740
(links normalized by FMF)
Hope that helps a little.
Cheers.
Phil
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nurbo
Joined: 23 Sep 2008
Posts: 457
Location: Lancashire
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Posted: Apr 08, 2012 12:12 Post subject: Re: Collection of Nurbo |
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That helps a lot, thanks Phil,
i tried to use mindat to look at Pyrolusite occurances in Lancashire and Cumbria, bit of a waste of time really, there are no sites on there in Lancashire where Pyrolusite is listed and there and only a dozen or so in Cumbria (Of which Stank is one).
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nurbo
Joined: 23 Sep 2008
Posts: 457
Location: Lancashire
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Posted: Apr 15, 2012 17:21 Post subject: Re: Collection of Nurbo |
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First up is a piece from an unusual locality, Gutterby Pit, its a Carbonate, (Aragonite or Calcite) on Dolomite, ex Lindsay Greenbank Collection, now in mine. Secondly a very nice Kidney Ore from Beckermet (!970's piece)
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Dolomite with Carbonate Beckermet Mine, Egremont, Cumbria, England, UK 5 x 3.5 x 2 cm |
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Dolomite with Carbonate Beckermet Mine, Egremont, Cumbria, England, UK 5 x 3.5 x 2 cm Showing Greenbank label with tabular Baryte |
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Hematite Beckermet Mine, Egremont, Cumbria, England, UK 9 x 7 x 5 cm |
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nurbo
Joined: 23 Sep 2008
Posts: 457
Location: Lancashire
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Posted: Apr 21, 2012 01:47 Post subject: Re: Collection of Nurbo |
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Im not sure if this is allowed but Ill do it anyway ....... I thought Id enter these, they arent in my collection as objects, though they would have been if it were possible, but the pictures are in my collection of photos, around late February I was working up in the field when I noticed many of the horses hoof prints had the most wonderfully defined Ice crystals, flat sheets of thin Ice had formed over the face of the cavities created in the mud by the horses hooves and fine Ice crystals had developed in amazing geometric formations on top of this. Ive always been fascinated by the formation of Ice crystals and snow but Ive never seen any like these before. The dimensions are approximate as I didnt have a tape measure to hand. The quality of some of the photos is unfortunately a bit poor.
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Ice Quernmore, Lancashire. Approx 20 cm across |
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Ice Quernmore, Lancashire approx 30 cms max dimension |
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Ice Quernmore, Lancashire approx 15 cms across. |
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Ice Quernmore, Lancashire approx 20 cms across |
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Ice Quernmore, Lancashire approx 15 cms across |
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Jordi Fabre
Overall coordinator of the Forum
Joined: 07 Aug 2006
Posts: 4902
Location: Barcelona
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Posted: Apr 21, 2012 07:05 Post subject: Re: Collection of Nurbo |
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nurbo wrote: | Im not sure if this is allowed but Ill do it anyway...
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Sure Nurbo. Nice Ice crystals! ;-)
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