68 pages, full colour.

UKJMM number 32 Shipping: UK (second class) £9.00 Europe (air mail) £12.00 Rest of World (surface) £12.00 Rest of World (air mail) £14.00

The Future of the UKJMM

Following the retirement of Jean Spence and Mick Wolfe, who have been indispensable members of the team for many years, there has been some uncertainty as to the future of the UK Journal of Mines & Minerals. We are pleased to report that the UKJMM will continue in its current form. With the support of subscribers, authors and advertisers, we will continue to develop the journal as a repository of information about British mineralogy.

UKJMM Issue 32 will be the last to be covered by current subscriptions. New subscriptions will begin from issue 33 with an additional option to pay using Paypal via the UKJMM website. Further details and information will be included in the next issue and on our website www.ukjmm.co.uk.

The Williams Collection

Many of us must have dreamed at one time or another of finding a collection full of fine old time mineral specimens. Courtnenay Smales has had the good fortune to discover and restore such a collection, which belongs to the Williams family of Caerhays Castle, Cornwall. Caerhays castle is situated in 120 acres of beautiful gardens in a secluded valley above Porthluny Cove. The gardens are one of Britain’s horticultural treasure houses, with a glorious collection of camellias, magnolias and rhododendrons.

The mineral collection at Caerhays was assembled between 1780 and 1890, in the heyday of Cornish mining, by several generations of the Williams family. It grew to be very large, ranking with the collections of Philip Rashleigh and Joseph Carne as one of the finest in Cornwall. There were considerable donations in 1893 to institutions including the Natural History Museum, London, the Camborne School of Mines and the Royal Institution of Cornwall, but some specimens were retained. These were dispersed to a number of locations and largely forgotten. Some specimens were piled five or six high in boxes and at first seemed a lost cause, but careful curatorial and identification work by Courtenay Smale gradually revealed many museum-quality specimens including remarkable copper secondaries from the mines of the Gwennap area, where the Williams family were mine owners. As well as Cornish material, superb specimens from the Caldbeck Fells, Leadhills-Wanlockhead, Derbyshire and further afield came to light. A small selection is figured on the frontispiece.

The gardens at Caerhays are open from 14th February to 5th June between 10 am and 5 pm, but the castle, where the mineral display is housed, is only open between 14th March and 30th May on weekdays from 12 noon to 4 pm. A visit is highly recommended. Further details are available at www.caerhays.co.uk.

Dolyhir Special Edition

As with the last issue, this edition of the UKJMM is given over in its entirety to a single article. We apologise to authors who have articles awaiting publication, and hope to produce a second issue of the journal with more varied content within the year. Dolyhir Quarry is one of the most important new British discoveries of the last decade, with numerous rare and unusual minerals, and we believe a full, well illustrated description is justified!

A superb old time classic specimen from the Williams family collection at Caerhays Castle. The largest modified cubic crystal on the blue fluorite is 35 x 31 x 28 mm. This specimen is unlabelled but is likely to be from Wheal Gorland, Gwennap, Cornwall.

Dolyhir Quarry near Old Radnor in Powys is developed in rocks of the Old Radnor Inlier, a kilometre-scale fault bounded block that lies within the Church Stretton Fault Zone. The quarry exposes Silurian algal limestones of the Dolyhir Limestone Formation, which unconformably overlie Neoproterozoic clastic sediments of the Yat Wood and Strinds formations. Mineralisation includes a limestone hosted lead-copper vein containing major primary tennantite, galena and baryte, with minor greenockite and enargite. Oxidation of this assemblage has produced supergene minerals including anglesite, azurite, cerussite, malachite, olivenite and tyrolite and rare arsentsumebite, gartrellite, otavite, segnitite and zincolivenite. Supergene enrichment processes have deposited a variety of copper sulphide minerals in the limestone including chalcopyrite, covellite, djurleite, roxbyite, spionkopite, yarrowite and probable geerite. Rich azurite and malachite commonly surround the copper sulphides. Realgar occurs as disseminations in fractures and joints in black shale of the Yat Wood Formation and in Silurian conglomerate. Vein hosted barium carbonate mineralisation comprises alstonite, barytocalcite, paralstonite and witherite. Fracture assemblages in the basement rocks contain anatase, baryte, calcite, edingtonite, harmotome, quartz, synchysite-(Ce) and ewaldite. Ore minerals are uncommon in the basement rocks, they include chalcopyrite, enargite, galena, luzonite, pyrite, sphalerite, tennantite and rarely proustite, wurtzite and xanthoconite. The vein assemblage in the Dolyhir Limestone is probably of the Mississippi Valley Type, but it is unlike any nearby locality. The realgar deposit is unique in Britain. The limestone hosted copper mineralisation records complex supergene enrichment and is unusually species-rich. The barium mineralisation is also complex and includes unusual paragenetic sequences. The mineralisation that has developed in fractures in the basement rocks is influenced by the local lithology and is diverse in comparison to other British localities. Dolyhir Quarry is the first British locality for ewaldite, geerite, roxbyite and xanthoconite and the first Welsh locality for arsentsumebite, gartrellite, luzonite, otavite, paralstonite, proustite, realgar, segnitite, wurtzite, yarrowite and zincolivenite. These rare species and complex parageneses make it one of the most important mineralogical sites in Britain.

57 pages.