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SOWERBY SCORODITE
Nick Carruth • Ron Cleevely
David Green
BECHERERITE
Steve Rust • David Moulding
David Green
ARSENTSUMEBITE FROM DOLYHIR QUARRY
Neil Hubbard • David Green
Tom Cotterell
WAVELLITE
David Green • Tom Cotterell • Ian Jones
David Cox • Ron Cleevely
PETITJEANITE FROM CARROCK MINE
Mike Rumsey • Trevor Bridges
John Spratt
NEW CLIFFE HILL QUARRY
Trevor Bridges


68 pages, full colour.

 

UKJMM No. 28
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Editorial:
Specialisation

David Green


For many collectors there comes a time when the uncritical acquisition of specimens ceases to be as fulfilling as it first appeared, coupled with the realisation that a vast expenditure of both time and money would be required to amass a truly world class collection. This often leads to specialisation. There are as many possibilities for specialisation as there are collectors, some are highly original (I well remember a display case full of specimens which looked like bow-ties), while others seem to suggest themselves time and again. Perhaps the two most popular specialisations are in the minerals of a particular locality or area and in a particular species or group. A collection need not exclusively develop in one specialist area, but it often helps to have one or more targets in mind as a focus for limited resources.

Specialisation can lead in interesting and unforeseen directions. In the last few years I have enjoyed choosing one of the less charismatic British mineral species and investigating its history and the localities where it is found, just to see where it leads. This kind of endeavour almost always produces a specialist collection. There are perhaps a couple of hundred British species which lend themselves to investigation in this way. These are typically minerals with a reasonable geographical distribution, perhaps an interesting history, not too difficult to
find at least at some localities, but challenging enough to remain interesting in the medium term. One project originated in a chance conversation overheard at the mineral show in Bakewell in 2004. Two collectors, discussing minerals over a sandwich, remarked that wavellite was a rather uninspiring species. Possibly true? But the more I thought about it, the more interesting it became. The type locality is, of course, at High Down Quarry in Devon, and wasn't it named after a local collector? Then there were surely good specimens from the clay pits in Cornwall and some nice green balls from Ireland, but where else?

Wavellite became more and more interesting. Tom Cotterell and Ian Jones had already made thorough investigations of the mineral’s occurrences in south Wales, and some of their specimens were quite superb. David Cox, a Devon-based collector who works at the Museum of Barnstaple and North Devon had amassed a considerable volume of information on the type locality and on William Wavell, the man after whom wavellite was named. Ron Cleevely had made an extensive study of William Gregor, the Cornish chemist and clergyman who analysed many early specimens. Eventually a story began to emerge and after many rewrites, additions and deletions it forms a twenty page article in this journal. It turned out that a lot of people were interested in wavellite. The list of references at the end of the article, begins with Richard Barstow and ends with Brian Young, it reads like a who’s who of British Mineralogy. Not bad for an ‘uninteresting’ mineral.

Which leads in a roundabout way to the point of this editorial: there are many species that would lend themselves to investigation in a similar way. Some such as calcite and barite would require a lifetime of dedicated effort to produce a collection that is anything like comprehensive. But what about British witherite, strontianite, harmotome, hemimorphite, quartz or for micromounters, anatase, rare-earth minerals, wulfenite or lead secondaries … They would certainly make good projects.

Minerals of the British Isles

Next year marks the 150th anniversary of the publication of Greg and Lettsoms’ classic volume on the mineralogy of the British Isles. This will likely pass, even in mineralogical circles, without much pomp or ceremony, but hopefully by the time of the sesquicentenary, a new volume, the first to describe the mineralogy of our islands in all of that time, will have been published by Terra Publishing. Proof-reading is still in progress as I write this editorial, but it is hoped that the book, by Andy Tindle, will be available in the Autumn of 2007. Minerals of Britain and Ireland will be a comprehensive treatment of all the minerals found in the British Isles. Illustrated with 500 colour and black and white images, it will provide exhaustive coverage of the remarkably wide range of minerals (more than 1000 confirmed species) found in Britain and Ireland. It will include notes on discredited species, fraudulent claims, type localities and all major museum collections. More information and a full review in the next UKJMM.


A Scorodite Specimen Figured by James Sowerby
and Analysed by William Gregor

Nick Carruth
Ron Cleevely
David I. Green

James Sowerby’s British Mineralogy is arguably the most important early illustrated description of the minerals of Britain and Ireland. More than a thousand specimens are painstakingly reproduced in 550 hand-coloured plates. Sowerby borrowed many of the specimens he figured from the collectors and scientists of the day. Relatively few of these have survived to the present. One of the last specimens illustrated by Sowerby was re-discovered in the early 1990s in the collection of Peter Golley. It is a scorodite from the parish of Perranarworthal in Cornwall, which was sent to Sowerby by the Cornish clergyman and chemist William Gregor. As the discoverer of the element titanium, Gregor has an honoured place in the history of chemistry. He analysed many other minerals, but did not have a personal collection. Very few of the specimens that passed through Gregor’s hands are known to have survived, and this makes the scorodite doubly important
3 pages.

Scorodite
Left. The scorodite specimen as a comparison to the illustration in British Mineralogy, which is reproduced in figure 4.
Right. James Sowerby's illustration of the scorodite specimen,as plate 547 in the final part of British Mineralogy. As with all Sowerby illustrations, it is a mirror image of the real specimen.

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Bechererite from Leadhills, South Lanarkshire and the
Charlotte United Mines, Perranuthnoe, Cornwall

Steve A. Rust
David Moulding
David I. Green

The rare zinc sulphate-silicate mineral bechererite occurs as minute inverted trigonal pyramids in leadhillite-lined cavities on a dump at Raik’s Vein, Leadhills, South Lanarkshire. It also occurs as a component of a white earthy crust at the Charlotte United Mines, Perranuthnoe, Cormwall. These are the first Scottish and Cornish reports of the mineral. In both cases bechererite appears to have formed by post-mining oxidation processes in spoil containing zinc-bearing minerals.
2 pages.

Horizontally striated trigonal bechererite crystals up to about 0.1 mm in length terminated by flat triangular pedion faces. Many of the crystals have unusual slightly curved nested morphologies. Raik’s Vein, Leadhills, South Lanarkshire. Steve Rust collection.

 

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Arsentsumebite from Dolyhir Quarry, Old Radnor, Powys

Neil Hubbard
David I. Green
Tom F. Cotterell

Arsentsumebite, a rare member of the brackebuschite group of minerals, has been identified as drusy crusts of curved blocky mint green crystals up to 0.1 mm on edge at Dolyhir Quarry, Old Radnor, Powys. It is found with anglesite and other lead-bearing secondary minerals in tiny cavities in oxidised lead- and copper-rich veinstone. The crystals are of near end-member composition. This is the first Welsh and second British report of the mineral.
2 pages.

A scanning electron microscope image of curved blocky arsentsumebite crystals up to about 0.05 mm on edge from Dolyhir Quarry. A small fragment removed from National Museum Wales specimen NMW 2007.1G.M.1

 

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Wavellite:
It's Discovery and Occurrences in the British Isles

David I. Green
Tom F. Cotterell
Ian Jones
David Cox
Ron Cleevely

Wavellite has been identified at about thirty localities in Britain and Ireland. It is typically found in folded sedimentary rocks of Carboniferous age and in the hydrothermal veins associated with granitic intrusions. Although it was recognised as a distinct mineral in the last quarter of the eighteenth century it is generally acknowledged that Sir Humphry Davy provided the formal description of the species in 1805. Davy proposed the name hydrargillite rather than wavellite, based on chemical analyses of the mineral, but these were later shown to be inaccurate and the name gradually fell out of use. The name wavellite honours William Wavell, a Devon-based physician and collector. There is controversy about the circumstances of the original discovery at High Down Quarry near Barnstaple. Some contemporary mineralogists claimed that Wavell was the first to recognise the mineral while others attributed its discovery to John Hill. Nineteenth century mineralogists confused wavellite with fibrous zeolite group minerals, with tavistockite and with diaspore, largely because of the difficulties encountered in making accurate chemical analyses. Modern techniques make wavellite an easy mineral to identify. The thirty or so undoubted occurrences in the British Isles are described and early errors, some of which have propagated into more modern texts, are highlighted.
20 pages.

Wavellite with variscite
Left. Translucent yellow-brown wavellite 3 mm across associated with a hemispheres of green variscite from High Down Quarry.
Right. Wavellite from Devon and Ireland reproduced by James Sowerby (1817, vol. 5, plate 433). The backdrop specimen is from High Down Quarry and is preserved at the Museum of Barnstaple and North Devon under accession number 1994.5.1. The four specimens in the foreground appear to be the first figured Irish wavellites. Sowerby’s rather confused text which accompanies the figure, and claims John Hill to be the first to find the species

Left. Pale mint green wavellite specimen 45 mm tall in fractured Carboniferous shale collected recently from Laharran Quarry, Minane Bridge, Co. Cork.
Right. Radiating yellow wavellite ball 19 mm across from Pwlldu Beach, the Gower, Swansea. Ian Jones collection.

 

Double page spread
Double page spread
Double page spreads from this article.

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The First British Occurrence of Paralstonite at
Dolyhir Quarry, Old Radnor, Powys, Wales

Tom F. Cotterell
Allan C. Dean

The rare barium-calcium carbonate paralstonite has been identified in mineralised tension fractures in dolerite and Precambrian sedimentary rocks of the Yat Wood Formation at Dolyhir Quarry, Old Radnor, Powys. It forms inconspicuous crusts of minute dipyramidal crystals in association with harmotome, alstonite, ewaldite, calcite and quartz. This is the first report of paralstonite in the British Isles.
5 pages.

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The Minerals of the Swiss Jura

Paul J. Andermatt

The Jura Mountains extend for about 270 km through northeastern Switzerland. They are made up of sedimentary rocks, primarily limestones, which were deformed and uplifted during the Alpine Orogeny. About 50 mineral species have been reported from the area. Calcite is abundant. Well crystallised specimens of celestite, dolomite, fluorite, goethite, gypsum, pyrite and sphalerite can also be found. A suite of uncommon soluble sulphate minerals has been identified in recent efflorescences and the rare sulphur polymorph rosickýite occurs in good specimens at the asphalt mines near Travers.
9 pages.

Double page spreads from this article.

 

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Harmotome from Ruthwaite Lodge Mine, Cumbria

Peter K. Todhunter

The barium zeolite harmotome occurs as dense encrustations of prismatic ‘core-bit’ twin crystals up to 2 mm in length on quartz and galena at Ruthwaite Lodge Mine, Grisedale, Cumbria. This is the first report from the English Lake District. Analyses by wavelength dispersive spectrometry produce the chemical formula: (Ba2.01,Ca0.01,K0.23,Na0.26)[Al4.66Si11.37O32]·nH2O. At Ruthwaite Lodge Mine, harmotome is overgrown by wulfenite and phosphatian mimetite, an unusual combination which does not appear to have been recorded elsewhere in Britain.
2 pages.

Wulfenite from Ruthwaite Lodge
Tabular wulfenite crystals to 2 mm showing two generations of growth with minor mimetite and harmotome on drusy quartz.

 

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The First British Occurrence of Petitjeanite at
Carrock Mine, Caldbeck Fells, Cumbria

Michael S. Rumsey
Trevor F. Bridges
John Spratt

The rare bismuth phosphate mineral petitjeanite occurs as small, dark brown, drusy crystalline aggregates in cavities in massive vein quartz at Carrock Mine in the Caldbeck Fells, Cumbria. Quantitative chemical analyses by wavelength dispersive spectrometry produce a chemical formula which can be written Bi2.99Ca0.05Al0.02Na0.01O(OH)[(PO4)1.65(AsO4)0.27(SiO4)0.07]. At Carrock Mine, petitjeanite is associated with a poorly defined russellite-like phase. Both are likely to have formed by the supergene alteration of primary bismuth minerals such as bismuthinite. This is the first report of petitjeanite in the British Isles.
4 pages.

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The First British Occurrences of Preisingerite and Roosevelite from
Carrock Mine, Caldbeck Fells, Cumbria

Michael S. Rumsey

Preisingerite and rooseveltite occur as grey glassy grains in fractures in massive vein quartz on an old museum specimen from Carrock Mine, Caldbeck Fells, Cumbria. The two species are visually indistinguishable and they are intergrown on a sub-millimetre scale. Quantitative wavelength dispersive spectrometry indicates that both are lead-rich. This has produced small distortions in the crystal lattices. The empirical formula for preisingerite is Bi2.69Pb0.17Fe0.06Ca0.03Al0.01[(AsO4)1.92(SO4)0.11(SiO4)0.02], and that for rooseveltite is Bi0.94Pb0.08Fe0.01Ca0.01Al0.01[(AsO4)0.93(SO4)0.05)]. Both minerals are likely to have formed by the supergene alteration of primary bismuth minerals such as joséite, bismuth and bismuthinite. This is the first report of preisingerite in the British Isles, and the first confirmed occurrence of rooseveltite.
3 pages.

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An Alternative Mechanism for the Formation of the Remarkable Copper Mineralisation at New Cliffe Hill Quarry, Stanton Under Bardon, Leicestershire

Trevor F. Bridges

An alternative mechanism for the formation of the remarkable copper deposit at New Cliffe Hill Quarry, based on a pond in a depression in the wadi where the deposit occurred is suggested and discussed in comparison with the oxidation of a hypogene vein proposed by Hubbard et al. (2005). It must be made clear that real evidence to support either mechanism does not exist, but it is hoped the discussion will be useful to future researchers in the area.
2 pages.

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Book Reviews

 

Robbing the Sparry Garniture: A 200 Year History of British Mineral Dealers 1750–1950
by Michael P. Cooper (2006)
David I. Green


 

Bonanzas and Jacobites: the Story of the Silver Glen
by Stephen Moreton (2007)
David I. Green

 

Goldscope and the Mines of the Derwent Fells
by Ian Tyler (2005)
David I. Green


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