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64 pages, full colour.
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Editorial
David Green
The UK Journal of Mines & Minerals is now in its twenty second year
and few of those who were instrumental in producing the first issue would
recognise the publication as it is today. Most of our sales are by subscription
and attention to some minor points will help us to ensure that the operation
runs smoothly and that you get your journal on time. It would be much
appreciated if correspondents would not staple cheques to their letters.
The staples can damage bank machinery. If payments are made using any
of the automated bank transfer
systems, please advise Jean Spence of the transaction in a separate letter
as the automated systems, particularly CHAPS, do not advise us of the
sender’s name or address. And if we do not know you have paid ...
Cheques should be made payable to Rockbottom Publications Ltd. This may
seem a strange and even inappropriate name. For recent or new subscribers
perhaps an explanatory paragraph is in order.
The name Rockbottom Publications is carried over from a local society
journal, Rockbottom, which was started in the late 1970s. The journal,
along with the society that funded it (the Doncaster Mines Research Group)
is now long defunct. However, the profits accrued from the sale of Rockbottom
were used to fund the first issue of the UKJMM. The name appears in the
first few issues, but was abandoned as the journal evolved. The company
name remains as an echo of the earlier Rockbottom and of the Doncaster
Group. It does not, as some have suggested, indicate a no-frills publishing
company!
Our feature on Kendal Museum in the last UKJMM highlighted some of the
problems that a small local museum has with a significant acquisition.
The UKJMM has supported museums from the outset and we have regularly
published articles on temporary exhibitions, new displays and major acquisitions.
In this issue we feature Buxton Museum, which has wonderful displays,
the geological highlight of which is a reconstruction of a petrifactioneers
workshop. Derbyshire craftsmen were famous in the nineteenth century for
producing inlaid
items, particularly in Ashford Black Marble. The finest twentieth century
collection was amassed by John Tomlinson (1918-2000). Staff at Buxton
Museum worked hard to acquire the Tomlinson Collection and finally managed
to do so in 2005. Curator Ros Westwood takes up the story…
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Unusual Banded Barite from Barras
End Mine,
Swaledale, North Yorkshire
Peter J. Briscoe
Dark brown barite, not dissimilar in colour to the
famous oakstone of Derbyshire, occurs on a few small dumps at Barras End
Mine in Swaledale, North Yorkshire. The barite, which is quite distinct
from the typical white North Pennine material, was deposited at a late
stage in open voids. Cavities within the massive banded barite are commonly
lined with translucent brown prismatic crystals. In some cases these are
overgrown by well crystallised hemimorphite. Strontianite, cinnabar and
aurichalcite are present on a few specimens. Cut and polished sections
commonly display attractive figuring.
4 pages.
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| Polished section
through a coarsely crystallised brown barite mass 40 mm across.
Photo Julie Ballard. |
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A double page spread
from this article
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Digital Combination Photography
of Micro-Minerals Using Bellows Lenses
David I. Green
Volker Betz
Software that combines the sharply focussed areas of
a series of digital photos offers significant advantages when imaging
specimens at magnifications greater than life-size. Traditionally, photographers
have used two methods to attain high magnification: photography through
the microscope or through specialised bellows lenses. This paper concentrates
on the second technique, using bellows lenses. To get the best results
it is important to understand the limitations of the lenses. In particular,
their depth of field and resolution at different magnifications and apertures
must be taken into account. If this is done properly, high quality images
of micro-mineral specimens with an enormously enhanced depth of field
can be produced.
10 pages.
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Left. Topaz crystals, the
largest 9 mm in length from Topaz Mountain, Thomas Range, Utah. This
specimen was photographed using a Zeiss Luminar 63 mm lens with minimal
bellows extension. The image is a combination of six digital photos.
It is about as large a reproduction ratio as is possible while maintaining
real detail in the image.
Right. Smithsonite crystal aggregates 2 mm long on manganese
oxide stalactites from Broken Hill, Australia. Photographed using
an Olympus 38 mm lens.
Multi-focus photos by David Green |
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Double page spreads from
this article
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Classic Nineteenth Century Fluorite Specimens
from Weardale, Durham:
A Mineralogical Mystery
Jesse Fisher
Nineteenth century mineral specimens from the North
Pennine Orefield in northern England are often only vaguely located. Where
there is any data at all they are usually labelled simply as “Cumberland”
or “Alston Moor”. Collectors and dealers commonly assume that
all the old-time specimens of green fluorite from the orefield originated
in the famous workings of Heights Mine near Westgate in Weardale. However
there is good evidence that some specimens with a distinctive matrix and
crystal morphology were found at the nearby Middlehope Shield Mine.
4 pages.
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| A cluster of twinned fluorite crystals, 10 cm
across, with minor galena, possibly from the 1818 find at White’s
Level on Middlehope Burn. Photo Jesse Fisher. |
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A double page spread from this article.
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A Mineralogical Tour of the
Kingdom of Fife
Stephen Moreton
The Kingdom of Fife on the eastern coast of Scotland
has a varied geology and has produced a considerable variety of mineral
species many of which are the result of volcanic activity. The north Fife
hills are particularly rich in agates. Pyrope and zircon are present in
a volcanic vent near Elie. Hydrothermal activity associated with volcanism
has produced quartz, calcite, dolomite and barite veins at several coastal
localities. At Orrock Quarry, apophyllite, pectolite and prehnite are
found in lavas. Some of the best pyrite crystals found in Scotland were
collected at Goat Quarry in the 1990s and traces of copper and uranium
mineralisation have been found in felsite at Balmullo Quarry.
7 pages.
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| Agates from Colluthie Hill near Luthrie collected
by Stephen Moreton. |
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The First British Occurrence of
Cesàrolite at Eaglebrook Mine,
Ceulanymaesmawr, Ceredigion, Wales
Tom F. Cotterell
The rare supergene manganese mineral cesàrolite
has been identified on a specimen from Eaglebrook Mine, Ceredigion, Wales.
It occurs as inconspicuous black botryoidal crusts in intimate association
with gibbsite. The X-ray powder diffraction data is compared with new
data for cesàrolite from the type locality and with published data.
A small systematic shift in the d-spacings (compared to the published
data) is attributed to improvements in instrumentation. This is the first
record of cesàrolite in the British Isles and the first report
of gibbsite in a supergene environment in Central Wales.
3 pages.
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Acicular Wurtzite and Sphalerite
from the
Lockridge Mine, Bere Alston, Devon
Ben A. Grguric
Ernest H. Nickel
The dumps of Lockridge Mine near Bere Alston in south
Devon contain rich specimens of mixed zinc, lead and copper sulphides
and sulphosalts overgrowing fluorite. Wurtzite-sphalerite intergrowths
showing the ‘ice-fern’ texture, which is characteristic of
wurtzite, are intergrown with silver-rich tetrahedrite, tennantite and
galena. Close examination suggests that most of the zinc sulphide was
deposited as wurtzite and then partially altered to sphalerite. A primary
hypogene origin is suggested for all of the minerals described, with the
excpetion of anglesite.
2 pages.
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Copper minerals including the
first Irish Clinoclase and Zálesíite
from Leaghillaun, Co. Kerry
Stephen Moreton
David I. Green
A small copper deposit discovered recently at Leaghillaun,
Beara, Co. Kerry, is a member of a large group of similar stratabound
base metal deposits that are hosted by the Devonian sandstones of southwest
Ireland. The primary mineralisation is dominated by tennantite and chalcopyrite,
which have oxidised to produce a suite of supergene minerals including
azurite, malachite, cornwallite, chrysocolla and tyrolite. The uncommon
copper arsenate clinoclase occurs as millimetre-size sheaves of dark blue-black
plates and the rare calcium copper arsenate zálesíite as
minute green acicular crystals. These appear to be the first reliable
reports of the minerals in Ireland.
4 pages.
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| Fan-shaped aggregates of platy
clinoclase crystals to 0.8 mm long. Stephen Moreton collection. Photo
David Green. |
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A double page spread from this article.
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The First British Occurrence of
Arsendescloizite at
Sandbed Mine, Caldbeck Fells, Cumbria
Tim Neall
Andrew G. Tindle
David I. Green
The rare lead zinc arsenate arsendescloizite occurs
as pale green crusts associated with calcium-rich mimetite at Sandbed
Mine in the Caldbeck Fells, Cumbria. Quantitative chemical analyses show
significant substitution of calcium for lead and of copper for zinc. They
produce a chemical formula that can be written: (Na0.07,Pb0.71,Ca0.22)(Zn0.73,Cu0.27)[(AsO4)0.94,(PO4)0.04,(VO4)0.01)](OH)0.97,
which is remarkably close to the ideal adelite-descloizite group formula.
This is the first report of arsendescloizite in the British Isles.
3 pages.
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| Pale green crustose arsendescloizite on iron
stained quartz with white calcium-rich mimetite from Sandbed Mine.
Field of view is ca. 3 mm across. Tim Neall collection. Photo David
Green. |
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The Composition of Tsumebite from
Roughton Gill Mine,
Caldbeck Fells, Cumbria
Andrew G. Tindle
Trevor F. Bridges
David I. Green
There is extensive substitution of arsenate for phosphate
in tsumebite from Roughton Gill Mine in the Caldbeck Fells, Cumbria. Calculated
chemical formulae are in excellent agreement with the general brackebuschite
group formula.The most arsenate-rich material has more than 50 atom% substitution
in the phosphate site and can therefore be described as arsentsumebite.
Arsentsumebite occurs as rims a few tens of micrometres thick, which surround
tsumebite cores. This indicates an increasing arsenate activity as the
mineral crystallised. Tsumebite is commonly found with well crystallised
brochantite and is often associated with slightly corroded cerussite.
This association provides an indication of the chemical conditions in
which it formed, probably at pH of about 6 with a high sulphate ion activity.
3 pages.
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| Apple green spherules of tsumebite (to
1 mm) with arsenic-rich exteriors, associated with dark green brochantite
and pyromorphite from Roughton Gill, Caldbeck Fells, Cumbria. Photo
David Green. |
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Caryopilite and Pyroxmangite
from
Nant Mine, Nant-Y-Gadwen, Llanfaelrhys, Pen Llyn, Gwynedd, Wales
Tom F. Cotterell
The rare manganese silicate minerals caryopilite and
pyroxmangite occur in thin veinlets cutting siliceous manganese ore from
Nant Mine, Nant-y-Gadwen, Llanfaelrhys, Pen Llyn, Gwynedd. Both occur
as microcrystalline orange-brown veinlets in massive manganese ore. This
is the first record of caryopilite in the British Isles and the first
account of pyroxmangite in Wales.
3 pages.
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