NORF LK MINERAL & LAPIDARY SOCIETYnorfolkminandlapsoc.homestead.com/Spring_2014.pdf · from SMLS, Norfolk, BMS / Russell Society, staying at the Hotel Accolo, a short walk from the

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STONE CHAT Vol.34 No.3

Spring 2014

Our Winter issue was produced in a bit of a rush as I had several health issues to address. I was therefore unable to proof read part of the material – hence the apology you will find in these pages. Sorry Georgie and to you all.

As Martin was recovering from his knee op , our scheduled talk due in February had to be postponed. It was replaced by one of our ever-popular Micro Nights. For those disappointed, all being well the Laurion event should be in April.

March once again brings us to our AGM, and we urge all who can to be there and support your committee. We do not expect any anything major to happen and it should be over in double quick time. It will be followed by a talk on Gunnerside Gill in the North Yorkshire Dales.

At the time of writing (late January) Club officials are going down like flies. Roy has had a fall and broken his right arm in two places, Martin is having a knee joint replacement and I am having an angioplasty procedure in a few weeks. Perhaps we should open a branch at the NNUH!

NORF LK MINERAL & LAPIDARY SOCIETY

COVER PICTURE:

Blue John bowl on display in Castleton Visitor Centre

WORKSHOPS

Two lapidary workshop days have been arranged for members, both experienced or beginners, as follows Tues 29 April at Martin’s home at Lyng (Richmond Place) Tues 15 July at Chis’s home at Gorleston

If you are interested, contact the hosts. Transport may be possible.

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50th

MUNICH SHOW

October 25 - 28th

2013

© Reproduced from SMLS Newsletter No. 247 by kind permission

This was my first visit to the Munich Show, and I thought that the 50th

Anniversary Show might be a good one to attend – I was not mistaken. I joined the mixed group from SMLS, Norfolk, BMS / Russell Society, staying at the Hotel Accolo, a short walk from the railway station in Feldkirchen, and only a ten minute bus ride away

from the Messe Munich Showground.

The Show opened to the trade on Friday morning and our host, Manfred Seitz, had kindly arranged to purchase some discounted tickets for us for 3 days at the Show. Figure. 1 captures Manfred (blue shirt looking towards the camera) on the Mineral Friends of Munich stand surrounded by minerals for sale and a batch of microscopes at the back for the micromount enthusiasts. This was our base and meeting point throughout the 3 days. Figure 2 shows our party heading for the Messe in good time for the opening at 09.00am – that’s Trevor Devon striding out in the lead (going pretty well, considering that he’s wearing John Pearce’s shoes, which were a size too big – see later!)

The Show entrance was like the starting gate at the Grand National – everyone jockeying for position and trying to make sure they were strategically placed to be

first through the turnstiles, heading for their particular first “target”.

I made a beeline for the special exhibit on gold, where some of the finest and largest specimens ever found had been assembled from museum and private collections across the world. I counted over 300 individual gold specimens ranging from exquisite single crystals from Venezuela, to the astounding Ausrox nugget discovered by a prospector using a metal detector in 2010 and weighing-in at 23.26kg (748 Troy ounces). There were a number of truly outstanding specimens – both for sheer size and aesthetic quality. The largest (and presumably most valuable) items were exhibited in glass-fronted safes, which nicely augmented the feel of being in a bank vault. Perhaps the most famous specimen is the so-called “Dragon” (Fig. 3), Colorado Quartz Mine, Mariposa County, California, from the

collection of the Houston Museum of Natural Science.

(http://en.wikipedia.org/wiki/Houston_Museum_of_Natural_Science)

The show occupied four halls (somewhat like the NEC in Birmingham), and these were Mineralworld, Gemworld, Stoneworld and Fossilworld respectively. The

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bulk of dealers and material of interest to myself and most mineral collectors was in Mineralworld – hall A5 and Fossilworld - hall A6 (Figure 4 shows an overview of hall A6) and this is where I spent most of my time. I did however do a circuit of the other two halls, and there were certainly interesting things to see and do in those areas as well.

There is an excellent, and well-illustrated on-line report of the show by Stefan Schorn (one of our local hosts in Munich), including a nice photo of our group at

the International Social evening.

http://www.mineralienatlas.de/lexikon/index.php/Events/Mineralientage%20M%FCnchen%202013%20-%20The%20Munich%20Show

Fig. 1 Manfred on the Mineral Friends of

Munich stand

Fig, 2 Trevor leads the way to the Show

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Photos were all Roy Starkey’s, except figures 4, 8 and 9 which were taken by Jolyon and Katya Ralph.

I’ll start by mentioning a few of the “outlying “areas and displays, and come back to minerals at the end. This year’s special exhibition in Stoneworld was called Set in Gold –

Precious Stones within

Christianity, and featured a selection of fantastic ecclesiastical treasures, together with some interpretative background information which made for an informative and aesthetic exhibit.

I was struck by the stand of the German Blind Association – titled Steine Begreifen – literally “grasping stones”, situated adjacent to the Treffpunkt

Forum. Here, visitors were invited to examine six specimens (in the dark) by touch and feel alone, and then to re-emerge into a display area where twenty specimens were laid out with labels. The task was to correctly match the specimens “seen” in the dark with the correct samples in daylight. For a reasonably competent mineralogist / geologist this was not difficult, and in fact I correctly identified them all in the darkened booth before re-emerging, but it did make one think about what the world of a partially sighted or blind person is like. I thought this was a really innovative idea, and maybe something SMLS might try at the Sussex Show

in association with RNIB.

Fig. 3 The Dragon gold specimen

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The gem and jewellery hall had the usual selection of countless thousands of beads and bangles, but also some really high class gemstones and jewellery (e,g. these superb carvings from Brazil – Fig. 5). I particularly liked a selection of tanzanite jewellery at the CHQ GmbH booth, but was accosted by one of the stand officials who snapped “Nicht photos!” – which I guess can be understood in most

languages.

Sadly this seems to be becoming more and more of an issue and is I think regrettable. I do not understand why people who are, after all, trying to promote their wares and get people to buy them, should feel

somehow threatened

Fig 4 Overview of Hall A6

Fig, 5 Superb mineral carvings on

the stand of Peter Muller, Brazil

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by enthusiasts wanting to take home an image to share with their friends. It is often said that there is no such thing as “bad publicity” and I would have thought in the case of selling minerals and gems that was certainly the case. I met with the same reaction on one or two mineral dealers’ stands when I asked for permission to take a photo, but in the main, there were plenty of “happy snappers”, and in fact at least

one collector was streaming live video of the show back to Japan from his iPAD!

The fossil display picked up on the theme of “golden discoveries in palaeontology”, and showcased some particularly significant fossils which have contributed to our understanding of evolution. Figure 6 captures a young visitor

admiring a Miocene Mastodon skeleton (Gomphotherium) at the Show.

Fig. 6 Young visitor checks out a Mastodon

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Back in the Mineralworld hall there was a second special exhibition called Treasury Carinthia featuring top-class finds from the Alps, and an opportunity to chip out your own garnet crystals from blocks of schist – great fun! The central pavilion was surrounded by a range of individual dealer stands and exhibits, including that of brothers Gerhard und Hannes Hofer (Fig. 7), strahlers who offer videos of their exploits. There are some great photos and some insight to their activities on their website here (http://www.alpinmineralien.com/). The efforts to

which these guys go in the quest for fine alpine cleft minerals is truly amazing.

In one of the outdoor areas adjacent to the Show halls was a popular exhibit of reproduction (plastic) dinosaur models. These were extremely life-like, and had been put on show by Wolter Design. Small ones start from about 2000 Euros, and range upwards to 10,000 Euros and beyond for larger ones. If you fancy one for the garden (Nick?) – see

http://wolterdesign.de/index.php?home

Fig. 7 Alpine quartz display Fig, 8 Crystal Classics – Bavarian style

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The main mineral hall was almost overwhelming. As is the case with Tucson, Sainte Marie and other major shows, there is almost too much to look at, and it is easy to miss things. The only solution seems to be to make serial circuits of the stands most likely to be of interest. The slice of wooden mine timber partially replaced with copper (Fig. 9) certainly caught my attention.

I collect only British minerals, and in the main, these were in short supply (with the obvious exception of Crystal Classics, who changed into Bavarian gear at the end of day 1 – Fig. 8 captures Diane, Elizabeth, David and Ian in costume. There were a few nice pieces to be seen on the stands of Wendell Minerals (http://www.wendel-minerals.com/default.aspx) and the Arkenstone - Rob Lavinsky (http://www.irocks.com/), although the prices of course were not for the faint-hearted. I will mention in passing that my vote for “case of the show” goes to the end case on the outer wall of Rob Lavinsky’s booth (Fig. 10)– it was simply outstanding, fantastic minerals, properly labelled, beautifully presented and not crowded. If you had to ask the

price, you couldn’t afford it!

Fig. 9 Slice of wooden mine

timber partially replaced

Fig 10. Rob Lavinsky’s choice cabinet with copper from Cyprus

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In addition to the dinosaur models outdoors, there were a good number of activities aimed at encouraging younger visitors. These included the ever-popular gold-panning, silver-smithing, digging / screening (in sand pits) for gemstones, carving talc, developing fossils using dental tools, knapping flints to manufacture axes and arrowheads, and undoubtedly the most popular of all (with youngsters and adults alike) splitting finely bedded like-mudstones from the Green River Formation of Wyoming in search of superbly preserved fossil fish. The Green River Formation of southwest Wyoming is famous for two distinct zones of very fine-grained lime muds, noted for preserving a variety of complete and detailed fossils. These layers are an Eocene Lagerstätte, a rare place where conditions were right for a rich accumulation of undisturbed fossils. The most productive zone—called the split fish layer—consists of a series of laminated or varved lime muds about 6 ft (1.8 m) thick, which contains abundant fish and other fossils. These are easily split along the layers to reveal the fossils. This thin zone represents some 4000 years of deposition. The accompanying photo (Fig.11) shows whole families happily

chipping away – now “that’s entertainment!”

Fig. 11 Getting down and dirty extracting fossil fish

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There are plenty of attractions in Munich apart from the Show.

On the Thursday afternoon before the Show I stopped off in central Munich with Michael Doel to visit the Museum Reich der Kristalle (http://inzumi.com/en/travel/point-of-interest/d_id/Munich/c_id/Sightseeing/p_id/Mineralogical-Collection). The museum is part of the Mineralogical State Collection in Munich and its origin was the valuable collection of the Dukes of Leuchtenberg. The permanent exhibition presents around 700 mineral specimens and gemstones. There are also exhibits explaining how minerals are formed, various applications as raw materials, and

something about their physical and chemical properties.

We had been recommended to visit an open air market on the Sunday morning and after two full days at the Show, seven of us did this led by Trevor Devon. Not only did Trevor navigate the group across Munich on the bus and railway networks, but he ensured that we joined the crowds of visitors in Marienplatz just before the bells struck 12 o’clock midday, gazing up at the tower in wonder as the highly coloured figures rotate as they record some of the history

of Munich (Fig 12).

On the Monday most of the group gravitated to the airport on their way home, but four of the group went into the centre of Munich to admire its superb architecture, the art galleries and the Science museum before taking a later flight.

Fig. 12 Spectacle in the tower at noon in Marienplatz

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The Editor [of the Sussex Newsletter]set a very tight space limit for this review, which could obviously be expanded greatly, so I’d better finish, but before I do,

back to those shoes ……

John Pearce had taken a pair of trainers to Munich so on the first day of the Show

he decided to wear the trainers to give his shoes (size 12/13) time to breathe. He

was a little surprised when he returned to the hotel room and found that his shoes

were nowhere to be seen. He thought that maybe the hotel management might have

decided they needed a clean, and other members of the group helpfully suggested

he should look under the beds or even in the mini-bar. John was sharing a room

with Trevor Devon and it was only when they both returned from a Social evening

organised by the local Micromount Society that John realised what had happened.

Trevor (foot size 10/11) had worn John’s shoes all day without realising his

mistake, although he did complain of some discomfort in his legs. The moral of the

story? Never share a room with anyone with feet of comparable size.

Finally, those of you who are reading this as the “electronic” PDF version will be able to make use of the various hyperlinks embedded in the text. This is one of the very real benefits of “electronic newsletters” – effortless access to background reading and material. For those of you working through the hard-copy (emphasis on the word HARD) – just give Colin Lansdell* a ring, or drop him an email, and

he’ll get you fixed up with an electronic version – just like that!

Many thanks to Richard Belson for organising this most interesting and successful trip, which went like clockwork; also Manfred and Regina Steitz for looking after us and inviting us to their International Social evening, where 70 people sat down

for a meal and provided a chance to make new contacts.

Roy Starkey * This has been – changed from “John Pearce” the editor of the Sussex Newsletter I hope it works for us too. CL

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Haltcliffe copper smelter and associated leat immediately

east of High Wath Ford have been scheduled as an Ancient

Monument Date first scheduled: 25-Jun-2001 Reasons for Designation Copper was extracted in Britain intermittently from the Early Bronze Age (about 2000 BC) until the early 20th century, after when the industry was confined to by-product production and small scale reworkings of mines and dumps. There is very limited evidence for copper mining before the 15th and 16th centuries, and most known sites are of later date, principally of the industry's 18th and 19th century peak after it had been revitalised by developments in smelting technology. In the 18th and early 19th centuries, as perhaps it had also been in prehistory, British production was important on a European scale. The smelting of copper to produce pure metal was a complex process involving prolonged and repeated roasting (heating without melting) before the roasted ore was broken up and melted to form a matte (a solid mass of copper and iron sulphides). This was followed by further roastings and remelting to refine the metal. Due to the multiple processes, the consumption of fuel was great, and smelting has typically been located close to fuel sources rather than to the mines. The use of the reverbatory furnace was developed in the late 17th century and dominated copper smelting from that date. Early reverbatory furnaces consisted simply of a barn-like building containing the furnaces, with chimneys projecting from the outer wall. The late 18th and 19th century smelt mills were often larger complexes containing several smelting furnaces and roasting furnaces for preparing the ore, together with systems of flues, condensors and chimneys for pollution control and the recovery of sulphur. Despite demolition of all buildings, the site of Haltcliffe copper smelter and its associated leat, wheelpit, slag debris, spoil heaps and dressing waste survives reasonably well. The monument is a rare example of a 19th century copper smelter in north west England, and together with buried remains of the smelting house and associated features it also retains abundant copper processing residues which contain significant technological information.

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The monument includes the earthworks and buried remains of Haltcliffe 19th century copper smelter and an associated leat east of High Wath Ford. It is located on the southern side of Carrock Beck and includes a leat, wheelpit, slag debris, spoil heaps, dressing waste and the buried remains of the smelting house. The precise dates when the smelter was built and when it ceased working are unknown; it is known to have been in use in 1866, however, it was not shown on maps of 1900 which suggest that it had been demolished by this date. Recent analysis of minerals found here indicate that the smelter served both the nearby Carrock End and Carrock Fell mines. A leat, which provided water power for the reprocessing of slags, survives as a narrow channel commencing a short distance downstream of High Wath Ford. This leat runs east for approximately 150m before terminating immediately above the narrow flood plain of Carrock Beck. At this point a gorse-filled hollow is considered to represent a wheelpit which housed the waterwheel used to power machinery at the smelter. On the beck's flood plain there are numerous features including traces of a short section of cobbled road or floor, areas of slag debris from the smelting process, and remains of a stone wall dividing two large areas of slag. A number of mounds and hollows at the southern edge of the flood plain represent a combination of spoil heaps and dumps of brick and slate from demolished buildings. Examination of the slag debris reveals that two of the areas of debris are heavily mineralised whilst two other areas show little, if any, mineralisation, indicating that varied smelting processes have taken place here. Book Reference - Author: Savage,K. - Title: Some Notes on the Haltcliffe Smelter -

National Grid Reference: NY 35116 35049 The above has been extracted from a document, on the Internet, by English Heritage. No. 1019957 Thanks to Martin Stolworthy for providing this item. The internet lists 23 minerals from this site including this Serpierite

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Thunder Eggs via Strata Gem, November 2009 via The Rockhound January 2010

Thunder eggs are lithic structures – rocks not minerals. Like other structures, such as nodules and geodes, they are formed, and found, in igneous material, rhyolites, welded tuffs or perlitic rocks. They have a knobby rind of drab, siliceous rock, often with a characteristic ribbed pattern. The inside of the outer shell has a relatively thin transitional lining of iron or manganese compound and/or opal or chalcedony. The centre cavity is filled with opal, chalcedony and/or agate, and it is this solid centre that distinguishes the thunder egg from the geode. In 1892, gem authorities from Tiffany’s gathered $20,000 worth of opal-filled eggs from a deposit in Oregon and the Thunder eggs have been the most popular “rock” in Oregon since. They were designated Oregon’s official state rock by the Oregon Legislature in 1965, the choice being supported by a 2-to-l vote by members of the mineral and gem clubs of Oregon and by the patrons of the Oregon Museum of Science and Industry (OMSI). Rockhounds have been collecting the eggs from Crook, Jefferson, Malheur, Wasco, and Wheeler Counties. Thunder eggs were similar to geodes at some point in their creation, once hollow and formed in a subterranean void, such as volcanic gas pocket. The processes of formation are still argued, some holding that the characteristic and unique internal pattern of typical eggs is due to expansion and rupture of rock by gases and others that it is due to desiccation (drying) of a colloid or gel. Whatever the process, once the egg is formed, further development is extremely variable in the amount of time needed to complete the egg, in the amount of infilling, and in the record of geologic events. Some eggs contain brecciated rock fragments, while others show faulting, offset, and healing. In some areas, it is common to find the characteristic chalcedony core weathered out of its shell. When sawed open and polished they may reveal the most exquisite and colourful designs ranging from five-pointed stars to miniature ocean scapes or gardens. Some of the finest and most famous thunder eggs come from deposits in the Richardson’s Rock Ranch in Oregon [example right] where the eggs dug out of a fragile perlite layer under a coal bearing strata. The eggs don’t get much bigger than baseball size and many of the best

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ones are no more than the size of a walnut but their colours and the patterns can’t be beat. The thunder egg agates of Succor Creek Oregon look like warty rocks or stony dirty snowballs when dug, but when cut and polished their distinctive agate is fabulous, clear and bluish grey with dark dendrites or white agate bands in a matrix flecked like granite and coloured from purple to white [see right]. Thunder eggs are sometimes found with fortification banding, horizontal layering, with any open area filled with clear chalcedony or inward-pointing quartz crystals, with some layers composed of a fibrous cristobalite (lussatite) or a partial botryoidal filling of an opal form of low cristobalite, opal fluorescent because of a low content of uranium salts. One collecting site in Oregon has eggs filled with carnelian; another, the filling may contain cinnabar, causing colours pastel to intense red, or filled with pastel jaspers. If you could cross an Oregon thunder egg with an agate from Northern Mexico, you would probably get something like the Deming Agate from the Baker Ranch in New Mexico [below].

Formed hundreds of miles from the volcanic activity that created the numerous Eastern Oregon thunder egg deposits, their eggs were still created by the same geologic forces. However, the eggs are sought for the fine fortification agate in brilliant colours that rival the agates of Lagunas and Moctezumas, typically red with black, grey, blue and

(rarely) yellow. They are rarely fractured and often have hollow centres with either a druzy, cinnamon centre, or well formed clear quartz points, or with long crystal stalactites that span the hollow centre of the stone, or one of these crystal formations yields a fine white feathery plume through the centre of the stalactite.

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BLUE JOHN

You may have heard that a ‘lost’ vein of Blue John has been rediscovered

atTreak Cliff Cavern at Castleton.

Briefly, an old time miner. John Royse, discovered a deposit of this fluorite in 1945 but died before he was able to pass the location on to the, then, new owners of the cavern. It has now been found hidden under an old piece of carpet and is expected to last for at least a decade.(the vein not the carpet) Well, I don’t believe we have covered Blue John in detail before, so here goes…..

Derbyshire Blue John (also known as Derbyshire Spar, or simply Blue John) is a semi-precious mineral, a form of fluorite with bands of a purple-blue or yellowish colour. In the UK it is found only at Blue John Cavern and Treak Cliff

Cavern at Castleton in Derbyshire. During the 19th century, it was mined for its ornamental value, and mining continues on a small scale.

Vein at Treak Cliff Mine

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Etymology

The most common explanation for the name is that it derives from the French bleu-jaune, meaning 'blue-yellow'. The story goes that Blue John was exported to France where is was used by ormolu workers during the reign of Louis XVI (1774–91). However, there is no archival record of any Blue John being exported to France,[1]:7 and the early ormolu ornaments which use Blue John were being manufactured by Matthew Boulton of Birmingham in the 1760s.

An alternative origin of the name derives from an old miners' name for the zinc ore sphalerite which they called "Black Jack". Thus the unique blue stone mined in these caverns could easily have become known as "Blue John".[1]:7

Another derivation comes from the Cornish miners who began working the Derbyshire lead mines in the 1740s. The name Blue John is used for several rocks in Cornwall, including fluorspars, and derives from the Cornish language word bleujenn, in Old Cornish blodon, a flower, bloom or blossom.[2]

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Geology

In the United Kingdom, the blue, banded, fluorite known as Blue John is found only under the triangular hill known as Treak Cliff, just outside the town ofCastleton.[1]:20 Today the veins are mined only in Blue John Cavern and the nearby Treak Cliff Cavern, although the abandoned Old Tor Mine on the north side of Winnats Pass was also, at one time, a source for the mineral.[1]:36

Mineralogy

The mineral veins of the Peak District were formed during the late Carboniferous and early Permian times, when the limestones were at a depth of 3 kilometres (1.9 mi).[1]:13 The minerals were deposited in veins by layers of crystals precipitating from hot fluids coating the walls of fractures, caves, and other cavities.[1]:17 Petrological analysis has shown that the Blue John, like fluorite elsewhere in the Peak District, crystallised from a highly saline fluid at temperatures of 90–120°C or perhaps a little higher.[1]:25

Despite much investigation, the origin of the blue colour of Blue John remains uncertain. Microscopic analysis has failed to find any impurities such asPotassium permanganate or hydrocarbons which could produce a

The entrance to Blue John Cavern

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purple-blue colour. It is now thought that the colour may be a physical phenomenon due to crystal lattice dislocation. If the regular arrangement of atoms in the fluorite molecules are disturbed or dislocated, then this may yield the blue colour in Blue John.[1]:27 The cause of these dislocations is unknown, but one possibility is that it is due to colloidal calcium, i.e. excess of calcium atoms needed to form fluorite.[1]:28 Blue John can be decolourised by heating it in an oven for a few hours, a phenomenon apparently caused by the heat realigning the lattice dislocations removing the colour. Irradiating the discoloured Blue John in an atomic reactor can bring the colour back.[1]:29

Similar rocks elsewhere

Blue, unbanded, fluorite occurs in many localities around the world. Within the UK, blue fluorspars are also found in County Durham, especiallyWeardale.[1]:39 Elsewhere, blue fluorspar is known in the Ardennes region of Belgium; the Cave-in-Rock area of Illinois in the USA;[1]:39and at various localities in Mexico and China.[1]:40

Blue-banded fluorite is very rare. An ornamental mineral known to the Romans as murrhine may have been a fluorspar similar to Blue John. Recently discovered deposits in China have produced fluorite with colouring and banding similar to the classic Blue John stone.[3]

History

It is sometimes said that Blue John of Derbyshire was discovered by the Romans.[4] However the earliest source of this story is William Adam's 1843 book Gem of the Peak. It seems likely that Adam was attempting to add some mystique to the Derbyshire Blue John.[1]:53 Although the Romans did mine lead in Derbyshire, there is no evidence that they encountered the Blue John veins.[1]:52

The earliest reference to the mineral "Blue John" occurs in a letter dated 1766 noting a lease from Lady Mazarine, which states that "Lady Mazarine let ye Blue John, Castleton".[1]:59 The next reference occurs in a 1768 letter by the industrialist Matthew Boulton who attempted to purchase or lease the mines so that he could mine the Blue John to create decorative vases (ormolu).[1]:64 It is clear that by this date the mining of Blue John had been going on for several years. The earliest dated decorative applications of Blue John in Britain are those in use as fireplace panels. The bridal suite of the Friary Hotel in Derby has a Blue

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John plaque dated to around 1760.[1]:69 About the same time, fireplaces with Blue John panels were designed by neoclassical architect and interior designer Robert Adam, and installed at Kedleston Hall near Derby.[1]:69

Later Output

By the 19th century Blue John was being fashioned into a wide variety of ornamental items ranging from knife-handles to chalices.[1]:73 The precise quantities mined in any given year are unknown, but 18th-century leases restricted output to 20 tons per annum. By 1892, the output is said to have been limited to 3 tons per annum. Today, production is probably around half a ton per annum,[1]:42 and the raw Blue John produced is kept within Castleton where small articles, mainly jewellery, are worked and sold.[1]:95 Elsewhere, similar blue and white-yellow banded fluorite ornaments are now imported into the UK and other countries from China.[7]

A hand polished specimen (from Flickr

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Literary References

The Terror of Blue John Gap is a short story by Sir Arthur Conan Doyle, which appeared in The Strand Magazine of 1910 and describes the experiences of a doctor who, while recuperating from tuberculosis on a Derbyshire farm, investigates mysterious goings-on in a cavern mined for Blue John.[8]

Alan Garner's 2003 novel Thursbitch features a cup made of Blue John,[9] which becomes one of the links between its two narrative strands.

References

1. ^ :a b c d e f g h i j k l m n o p q r s t u v w x y z aa ab ac ad Ford, Trevor D. (2000). Derbyshire Blue John. Landmark Publishing. ISBN 1-87377-519-9.

2. ^ George, Ken (2009). An Gerlyver Meur: Cornish-

English, English-Cornish Dictionary. Cornish Language Board. ISBN 1902917847.

3. ^ Ford, Trevor D. (1994). "Blue John fluorspar". Geology

Today 10 (5): 186. doi:10.1111/j.1365-2451.1994.tb00422.x.

4. ^ :a b "History of the Blue John Cavern". Official site of Blue John Cavern. Retrieved September 2010.

5. ^ The Crawford Cup, British Museum, retrieved 26 October 2012

6. ^ The Barber Cup, British Museum, retrieved 26 October 2012

7. ^ Graham Hill, John Holman (2000). Chemistry in

context. ISBN 0174482760.

8. ^ Conan Doyle, Arthur (1910). "The Terror of Blue John Gap". The Strand Magazine 40 (236).

9. ^ Garner, Alan (2003). Thursbitch. The Harvill Press. p. 22. ISBN 978-0099459361.

Much of the above from Wikipedia

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POLISHING TIPS

Agates – Cerium Oxide on Canvas Amazonite – Tin Oxide on Leather Apatite – Line A on Leather Amber – Tin Oxide on Leather Aventurine – Tin Oxide on Leather Azurite – Tin Oxide on Leather Beryl – Cerium Oxide on Canvas Bloodstone – Lin A on Canvas Celestine – Tin Oxide on Leather Chrysoberyl – Diamond Paste on Wood Chrysocolla – Cerium Oxide on Leather Coral – Tin Oxide on Leather From the Summit Lapidary Club Inc. Ohio, USA via PGMC

These tips have not been tried by the editor so there is no guarantee that

they work.

Many lapidarists now heat nodule and thunder egg halves under a heat lamp

for a few minutes before polishing with tin oxide or cerium oxide on felt.

The polish comes up almost instantly. Alternatives include putting

specimens in a 200° F oven until they are warm to the touch or putting

specimens in hot water until they are warm. Dry off excess water before

polishing.

To spot cracks and vugs before sawing, first soak it in a tub of water for at

least an hour. Remove the rock and place it in a sunny spot. The surface will

dry quickly, but the fractures and vugs will not. Use a soft pencil to mark the

rock for guidance in sawing.

From Rockhound Gazette March 2012

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• Silver findings may be polished by filling a tumbler one-third full of shredded newspaper. Place the findings in the barrel and tumble for a few hours. Do not use any polishing compound and tumble dry.

• Turquoise: never use ammonia, soap or detergent on turquoise; ammonia will turn the turquoise white. A drop of ammonia on a scrap piece is a good test to see if it is genuine.

From Arrowhead News, Nov. 2008 via PGMS 1110

Stabilizing porous stones:

If you would like to try your luck at stabilizing porous stones such as turquoise, so that it can be ground into shape and polished, then take a glass jar with a lid, add half a litre of acetone, add the complete contents of both the resin and the hardener tubes of epoxy glue. Mix well, add clean and dry stones. Cover the jar and let it stand for at least 4 days. Remove the stones and allow a week for them to dry completely. They should now be ready to be worked with.

Come on you “Cabbers” give it a try and let us know if it worked. Keep rocking, John Bruigom

Source: SA Lapidary Magazine, Nov. 2006 via Pretoria Rockhound Digest

The following were some of the tips noted during the February meeting of the Beehive Rock & Gem Club: • Diamond trim saws of 6 to 10 inches are most commonly used for making cabs. Some types use water and have rust resistant blades while others use oil (if water is used they must be drained each time used or they will rust out quickly. • Use a soft brick to “sharpen up” diamond blades. This cuts away some of the metal to expose diamond edges. • Diamond grinding and polishing equipment has distinct advantages to the older and less expensive silicon carbide equipment (not as messy, quicker results, not the wheel dressing needs, etc). • Silicon carbide wheels need to be turned to spin out excess water at the end of work so they don’t soften up or come apart. They need to be trued up if wear is uneven across them. • You don’t need to have a water hookup as you can use sponges to wick the water to the wheel from the tray. • Use the whole wheel (diamond grinder) by starting your rough grind on the edge parts and finish more towards the middle to keep from catching an edge.

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• Don’t “EVER “ - drain cuttings or water from your equipment down the drain (unless you want to buy a new sewer system). This stuff sets up like cement in your pipes.

• Cat litter is a good to absorb oil out of slabs that have been cut with an oil saw. Some dish soap and water help finish the cleaning. • Agate is more forgiving to work for cabs than

softer rocks & easier for beginners for that reason. • Templates of different sizes and shapes help to “pre-form” type cabs for which there are metal findings (settings) in silver, etc are readily available so you don’t have to be a silversmith. Free form cabs usually require special custom settings or wire wrapping. • 3/16th is the most common thickness cut for cabs. For higher crowned cabs or double sided cabs greater thickness are needed. • Rocks that require great care grinding as dust can be harmful include: Tiffany Stone, copper ores (Malachite, etc) and shells. More water and masks help. • Many types of things can be used for Dop Sticks including nails, flat end bolts, etc, The use of double sided tape to attach the rock was of special interest. • Salvaging thin cuts and special types of fractured rock by gluing on doublets with epoxy then finishing a cab was intriguing. Also by changing the colour of the base under translucent or thin types of material can change the appearance and colour of the cab. • By using vinegar or another acid based product with the polish (tin oxide) can quickly bring out a high glossy finish. • A methodical approach is needed to work larger and flatter cabs as ―flat spotsǁ become a nemesis to good work. • Check cabs when they are dry rather than wet when moving through grit sizes to see the scratches which need to be removed. • One of the steps includes cutting a slight bevel in the underside of the cab to prevent chipping at edge points.

Assembled by Rocky Ray of the Beehive Rock & Gem Club via Rockhound Gazette 04/12

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Bubble Lace Agate

Illustrated is a pendant created by Georgie Sturmy recently. The spectacle

setting (i.e. viewable on both sides} in sterling silver contains a Mexican

Crazy Lace Agate.

This super rare type of lace agate is rarely seen any more it is sometimes called Noreiga lace agate and is the most defined of its type and highly prized by collectors. My Lexicon Records - Noriega Lace Agate, near Benito Juarez, Chihuahua, Mexico. Cross* (1996.p.74) stated the name was derived from Juan Noriega, one of the pioneer miners in the original lace agate claims in the Sierra Lucia. It is a vein agate that has formed in marine limestones of of late Creaceous age.

* Cross, B.1996 The Agates of

Northern Mexico , Burgess International Group, Inc. Burgess

Publishing,Edina, Minnesota

Georgie Sturmy & Colin Lansdell

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In a recently purchased American book* I came across a reference to Stockdale Beck agates. On e-mailing the author she was unable to give me the location more accurately than “Cumbria” so I had to find it for myself.

The first thing I found was a synopsis by the Dept. of Earth Sciences, from which the following extract is quoted:

‘Metamorphic effects on agate found near the Shap granite, Cumbria,

England: as demonstrated by petrography, X-ray diffraction and

spectroscopic methods

Agates from a 430 Ma host at Stockdale Beck, Cumbria, England have been characterized. The crystallite size of the Stockdale Beck agates was found to be ~60% greater than any other agates from five regions aged 400-1100 Ma. Raman spectroscopy identified moganite in all agates tested except those from Stockdale Beck. Infrared spectroscopy showed that the silanol content of the Stockdale Beck agates was near zero. The properties of agates from Stockdale Beck and the 1.84-3.48 Ga metamorphosed hosts found in Western Australia were similar but different from agates found in other hosts aged 400-1100 Ma. Cathodoluminescence demonstrates further differences between agates from hosts aged 13-1100 Ma and those from Stockdale Beck and Western Australia. Agates from the latter areas have a lower proportion of defects causing a red emission band (~660 nm) but an increased proportion of defects causing blue (~470 nm) and orange (~640 nm) emission bands. Agates found in hosts aged 13-1100 Ma are also differentiated from the Stockdale Beck and Western Australian agates in a ternary plot of the relative intensities of violet to blue to orange emission bands. Single scans producing this combination of colours are only found in the Stockdale Beck and Western Australian agates. The properties shown by the Stockdale Beck and Western Australian agates demonstrate that an agate or chalcedony infill can be used to identify post-deposition palaeoheating within a host rock.’ This synopsis was originally taken from: Mineralogical Magazine, August 2007, Vol. 71(4), pp. 461–476 and is by Moxon, T. et al * Brzys, Karen A., Agates Inside Out, 2010 Gitche Gumee Agate and History Museum, Grand Marais, Michigan Stockdale Beck is situated approximately 10 km north of Kendal at the northern end of the Longsleddale valley at NY 49182 05469. I can supply fuller directions on request. I regret that copyright restrictions do not allow me to show an agate.

Colin Lansdell

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ROMAN EMPIRE

Power & People

At the Norwich Castle 1 Feb – 27 April

Roman Empire Exhibition explores the story of one of the most powerful empires the world has ever seen, and includes over 160 stunning pieces from the British Museum. Norwich Castle is one of only six UK venues to host this remarkable exhibition. Highlights include sculpture from the villas of the Emperors Tiberius and Hadrian, coins from the famous Hoxne treasure, beautiful jewellery and near-perfectly preserved children’s clothing from Roman Egypt. The exhibition explores the wealth, power and organisation of the Empire, but also how the Romans viewed their provinces and other peoples. Religious, military and personal objects give an insight into the lives of people from northern Britain to Egypt and the Middle East. Fascinating artefacts from the Castle’s own collections will also be on show, including important religious objects, magnificent glass and pewter vessels and wonderful Roman jewellery. Remaining Tuesday lunchtime talks 12.30 – 1pm 4 March - Becoming Roman? The Empire and East Anglia 18 March – The Roman Glass Industry-An Innovator’s Paradise 1 April - Egypt under the Roman Empire 8 April - Personal Adornment and Identity in Roman Norfolk

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Mar 1-2 Rock Gem & Bead Fair Cheltenham Pittville Pump Rooms

Mar 8-9 Oxford Colloquium Visit www.ogg.uk.om Mineral Symposium, Geofest 2014, Lectures, Field Trips, etc.

Mar 8-9 Rock & Gem Fair Kempton Park Racecourse

Mar 9 Oxford Mineral & Fossil Show

Exeter Hall, Kidlington, N.Oxford

Mar 22-23 Rock Gem n Bead Fair Brighton Racecourse

Apr 12-13 Rock Gem & Bead Fair Newton Abbot Racecourse

Apr 26-27 Rock Gem n Bead Fair Newark Showground

May 3-4 Rock n Gem Fair Bath & West Showground, Shepton Mallet

May 10-11 Rock Gem & Bead Fair Newmarket Racecourse

May 11 Oxford Mineral & Fossil Show

Exeter Hall, Kidlington, N.Oxford

Jun 7-8 Rock n Gem Fair Kempton Park Racecourse

Jul 5-6 Rock Gem n Bead Fair Newcastle Racecourse

Jul 14 Oxford Mineral & Fossil Show

Exeter Hall, Kidlington, N.Oxford

Jul 25-27 NAMHO Annual Conference

Bangor University, Gwynedd

Aug 2-3 Rock n Gem Fair Kempton Park Racecourse

Aug 9-10 Rock n Gem Fair Royal Welsh Showground, Builth Wells

Aug 16-17 Rock Gem & Bead Fair Pavilions of Harrogate, Showground

Sep 14 Oxford Mineral & Fossil Show

Exeter Hall, Kidlington, N.Oxford

Sep 20-21 Rock Gem n Bead Fair Newark Showground

Oct 4--5 Rock Gem n Bead Fair York Racecourse

Oct 11-12 The Rock Exchange Lady Manners School, Bakewell`

Oct 25-26 Gem n Bead Fair Newton Abbot Racecourse

Nov 1-2 Rock n Gem Fair Kempton Park Racecourse

Nov 8-9 Rock Gem n Bead Fair Pittville Pump Rooms, Cheltenham

Nov 22-23 Rock Gem n Bead Fair Brighton Racecourse

Nov 30 Oxford Mineral & Fossil Show

Exeter Hall, Kidlington, N.Oxford

IT LOOKS AS THOUGH EARLY MARCH IS GOING TO BE A

BUSY TIME – PARTICULARLY IN OXFORD!

I have just found this in GeoSuffolk Times and didn’t have space for it elsewhere. ‘Norfolk Museums and Archaeology Service’s Shine a Light project will display the West Runton Steppe Mammoth at Gressenhall Farm and Workhouse collections superstore from next summer [2014]; it may then be viewed through tours, events and online.‘

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NORFOLK MINERAL & LAPIDARY SOCIETY

Founded 1973 Affiliated to G.A.

Chairman: Christopher Marsh, 25 Carrel Road, Beacon Park, Gorleston, NR31 7RF � 01493 604778 � [email protected]

Vice Chairman & Field Trip Co-ordinator: Richard Belson

� 01603 413003 � [email protected]

Secretary and Editor: Colin Lansdell 10 Lorraine Gardens, Norwich, NR3 4DH

� 01603 404833 � [email protected]

Treasurer & Membership Secretary: Peter Smith, 15 Pitchford Road, Norwich, NR5 8LQ

� 01603 471536.� [email protected]

Web Master: Martin Stolworthy, � 01603 872420 � [email protected]

MEETINGS: 1

st Tuesday of most months at the Catholic Church Hall,

Churchfield Green, Thorpe St Andrew, Norwich from 7.30pm.

Stone Chat is the quarterly publication of the society and reproduction of articles is allowed (unless stated otherwise), provided source and author are acknowledged. Opinions given in this publication are those of the author and not necessarily those of the Society. Information given by a writer is not always checked for accuracy. Articles are accepted for publication on the understanding that they do not infringe copyright laws (past or present) and that this is the responsibility of the author.

www.norfolkminandlapsoc.homestead.com/