Linarite Nantycagle mineAt first this article was going to be just about linarite. It very soon became apparent that schmiederite would play a late but important part in the history of linarite from the UK.Many collectors have fine examples of linarite in there collections, from a number of UK and world locations. It is easy to understand why. Who would not like to have in there collection a azure blue bladed radial crystal group of linarite, con..

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At first this article was going to be just about linarite. It very soon became apparent that schmiederite would play a late but important part in the history of linarite from the UK. 
Many collectors have fine examples of linarite in there collections, from a number of UK and world locations. It is easy to understand why. Who would not like to have in there collection a azure blue bladed radial crystal group of linarite, contrasted against a back ground of white quartz.
While linarite is of wide spread occurrence it is still an uncommon and fine prize to find.
Schmiederite is a mineral only known from a few localities world wide, but has not yet been been found in specimens to compare with linarite.

The known history of linarite has been traced back to at least the early 19th century, while schmiederite is of very recent appearance on the mineralogical scene (1963). 
It would appear that James Sowby was the first to publish a picture of linarite in his book of 1809, although he called it Crystallized Blue Carbonate of Copper. The sulphate content of linarite was over looked,or not understood. 
Later Henry James Brooke recorded the name cupreous sulfate of lead. Having changed from a carbonate to a sulphate in 13 years.,due to better chemical analysis. It was not until 1839 the species was given the name linarite by professor Ernst Friedrich Glocker,from the type location at Linares, Jaen province, Andalusia, Spain.

Linarite PbCu(SO4)(OH)2 usually forms thin bladed monoclinic crystals, and stubby crystals with little development of the prism faces, examples can be seen from the Waterbank Mine, Ecton, Staffordshire. Colour can be from light to deep azure blue. Linarite usually occurs in lead and copper deposits, while this is true it is a very general statement. Linarite can also be found in many other ore deposits, which might have only small amounts of primary lead and copper minerals,from which linarite can form.

In the United Kingdom some the of best macro examples of linarite have come from Redgill and Roughton Gill mines. Although it is believed that at least some Roughton Gill examples may have come from Redgill or visa-versa. Roughton Gill has been used as a generic name for the Caldbeck Fells area. Classic specimens of thick bladed crystals of linarite to 2.5 cms long where collected from Roughton Gill and Redgill mines in the 19th century, fine examples are in the NHM London collection, and a few museums around the world. Good micro specimens could until recently be found at these locations with some hard work. Linarite is also found at a number of other mines in the Caldbeck Fells area. Particularly the Driggith Mine, where crystals to 1cm are said to have been found, and also at Silvergill mine.


 

Excellent linarite micro crystals are found in slag at the Stonycroft Smelter dump with several other Cu and Pb secondary minerals.


 

Comparable specimens to those from the Caldbeck Fells were also collected in the same period from the Leadhills-Wanlockhead mining area. Where linarite was found in crystals to 1cm. From this classic mining area good micro-specimens can still be found . Over the years with the upsurge of micro mineral collecting and old reports a number of the veins in this area have produced examples of micro linarite. For example it has been found on old dumps at Horners Vein, Lady Ann Hopetoun Shaft, Brow Vein, Hopefull Vein, Susanna Mine, Old Glencriff Vein, Cove Vein, Bay Mine, Belton Grain Vein.

 

 

Excellent specimens of linarite are also note worthy from the Meadowfoot Smelter slags, were fine deep azure blue micro crystals to 2mm are found associated with a number of basic sulphates of Pb,Cu and Zn, mostly colleced in the 1980's to date.

Also to a much lesser extent linarite has been noted in slags from the old Glencriff Smelter.


 

 

 

Wales!. Well what can be said about linarite from particularly mid-Wales. It almost seemed in the early years of the British Micromount Society. If you went to any mine dump it was going to produce micro linarite specimens.
This was not at all true! and usually entailed a lot of investigation. And lots of digging had to be done to find the elusive examples of linarite.

Only the most noted locations are represented here.

Certainly the most prolific site for fine micro crystals of linarite has been the Eaglebrook or Nantycagle Mine (a name I much prefer) on the west side of Nantymoch Reservoir. The site has been known since at least the mid to late 1960’s to my knowledge. And can be considered a bench mark for micro linarite specimens from the UK. The dumps (mostly East Shaft) produced not only fine linarite, but a number of supergene copper, lead and zinc minerals. Linarite’s from this location are found as excellent micro crystals to 2 mm + forming fine divergent groups and radial sprays, in a gossan matrix. And as contrasting azure blue crystals on white quartz veinstone., sometimes covering areas to a couple of cms.


 

 

 

About 2 kms to the north is Esgair Hir Mine, at this location while linarite is far rarer. Specimens are of a comparable quality to those from Nantycagle. Excellent linarite specimens have been found as carpets of divergent micro crystals covering areas to 1.5cms. The mine also produces a wide range of supergene species mostly collected from the Early 1980's to date.

 

 

 

A fairly recent find of linarite has been from underground in the adit level at Henfwlch mine where it was noted as crystal sprays to 2 mm.


At the Geufron Mine occasional fine linarite micro’s are seen as single scattered bladed crystals to 1mm with anglesite and cerussite in quartz cavities. And some times as flat radial groups of crystals to 4-5mm diameter on partings in mudstone.


 

 

A few kms north is the Dylife Mine, most of the good linarite’s came from a small dump south of Penycrocbren hill.
Here many of the linarite crystals are quite broad almost tabular to 1.5mm. Forming single crystals and small groups. The more usual bladed habit is also to be found here. A number of other supergene species are associated., mostly collected in the late 1960's to date.


 

 

Frongoch Mine near Devils Bridge is a location where I have done a lot of work,( I still go back once in a while). Frongoch mine was extensively worked in the 19th century by John Taylor & Co and John Kitto. And is one of the few mines in mid-Wales to be worked by steam, with it’s now ruinous Cornish engine houses.
Most specimens where collected from dumps afew meters in front of the engine houses and are probably some of the oldest. The supergene minerals are found in cavities in a quartz veinstone and grown on deeply etched galena . From an over view of the many supergene Cu,Pb,and Zn species that have been found at Frongoch. It can be seen that by far the most common is cerussite, while pyromorphite is rare. The basic sulphate assemblage plays a very subordinate roll. Linarite is comparatively scarce in the supergene paragenasis a lot rarer than susannite. Even so it does produce some rather nice crystal examples, as broad to elongated bladed forms to 1 mm. The pyromorphite and cerussite from this mine were probably first collected in about 1850. While the basic sulphate assembleage was not taken seriously untill at least the late 1960's


 

 

 

At Cwmystwyth Mine some very good rare micro linarite crystal sprays to 2 mm have in the past been collected from the so called copper level. The linarite and several other supergene species where found undergroubd in a quartz vein very near to the surface partly over layed by glacial boulder clay. The first collecting appears to have been in the late 1970's.

 

 

Penrhiw Mine has produced some fair examples of radial linarite crystals to 4mm diameter, with ramsbeckite and schulenbergite in a partly oxides ankerite-quartz-mudstone veinstone. Collected in the late 1990's

At Nantymelen Mine the dumps have been much depleted by foresty plantation., but what is left still comes up with the odd rare specimen of linarite. The mine has the honour of producing some of the largest crystals from Wales, occasionally up to 4 mm.

Several other mines in mid-Wales have produced the odd good linarite micro specimen, but they are rare. 

In north Wales linarite has been found at the Llangynog mine in old dumps above the dolerite quarry. Derived from a mineralised fault between the dolerite and slate. Here the supergene minerals have formed in cavities to 1cm+ in an oxidised quartz-ankerite veinstone with remnants of chalcopyrite, sphalerite and galena. Fine deep azure blue bladed crystals of linarite are sometimes found lining or scattered in these cavities, with other supergene species.


 

 

 

In Shropshire good specimens of linarite were once found in the dumps of the Ladywell Mine with wroewolfeite and other supergene species, collected in the late 1960's. The site has since been cleared.

Waterbank Mine, Ecton. This old mine has produced some very nice linarite micro specimens. Which are of a simular qulity to those from Nantycagle mine in Wales. And is one of the first know occurrences of ramsbeckite and schulenbergite from the UK. As well as the first known find of olsacherite in the UK.
The linarite from this location forms two distinct crystal habit’s, which seem to be present in equal amounts. As well the usual bladed type in single crystals and rare radial groups to 1mm +. It is also found as stubby single crystals and groups showing only partial development of prism faces.


 

 

 

From Cornwall probably the two best Linarite occurrences are Penberthy Croft Mine, and further north at the Pentire Glaze Mine. There are several other locations, but mostly only produce poorly developed crystals.

Linarite from Penberthy Croft Mine is rare, the mineralogy is mostly dominated by fine micro-crystals of iron, lead and copper arsenates. When it has been found, linarite is commonly in thin bladed crystals to 2mm covering areas to a rare 2cms. Very rarely does it develop thick more substantial crystals.

 

 

Pentire Glaze Mine is better know for its large fine groups of jack-straw cerussite. Linarite is quite rare from this mine, but occasionally produces the odd good micro.

From Devon linarite has been found at Frankmills Mine and Wheal Exmouth commonly as crusts on slate surfaces, and encrusting etched flat laying prismatic crystals of cerussite to 2cms+. Only rarely have I seen free grown thin bladed linarite crystals from the dumps. A number of years ago at Frankmills someone had driven short a level in to the lower part of the dump for about 1.5mts (and it was possible to collect linarite from here then). This was shored up by corrugated iron sheet and lumps of timber, it actually looked quite stable at the time. 

 

Schmiederite

 

 

A very rare mineral only found at a few world localities, originally noted in 1963 from the Condor Mine, Los Llantenes, La Rioia, Argentina. And known from a hand full of other localities world wide. Also has a monoclinic structure and forms a solid solution with linarite.

In the UK many linarite specimens from certain areas have elevate levels of selenium in there chemical structure, particularly in those from mid-Wales. This could be due to the siltstones and mudstones of this area, originally contained a high probable organic content concentrating the selenium. In 1989 a specimen from Llechwedd Helyg Mine, mid-Wales, was submitted to the NHM London. The specimen had a number of sub-millemeter sized light blue balls scattered over a quartz veinstone. I was not convinced it was linarite, and was unsure of what it might be. As it turn out it was to be the first confirmed find of schmiederite in the UK. Although it was only just on the schmiederite 50-50 side, and should really be considered a sulphatian-schmiederite. This may also be true for many of the so called schmeiderite specimens recorded from the UK. It is imposable to visually distinguish between linarite and schmiederite from these locations. Light blue balls and small botryoidal crusts from mid-Wales are more likly to be at least selenium bering linarite.

At Llechwedd Helyg Mine sulphatian-schmiederite is a very rare mineral where it forms scattered light blue balls to 0.5mm in and on a quartz matrix. And as small nice bright blue crusts 8 mm2 composed of minute lath-like crystals. Llechwedd Helyg mine is the only confirmed example of schmiederite from mid-Wales. Other surposed schmdierite have been shown to be linarite, although some with a high selenium content. 

From the Meadowfoot Smelter, Wanlockhead., schmiederite has been very rarely found forming small mm sized crusts of minute very pale purple-blue lath-like crystals in the slag.

Greystone Quarry in Cornwall is a recent addition to the locations for schmiederite. Where it forms very rare crusts of pale blue to white tipped lath crystals to less than 1mm. Again how far over the 50-50 linarite-schmiederite line these specimens are is not recorded.

Waterbank Mine bule balls to 0.25mm identified on two specimens which also had Olsacherite in association. Are likely to be linarite-schmiederite, analysis has shown a high selenium content.

Refs:-

Bevins, R.E., 1994. A Mineralogy of Wales National Museum of Wales, Geological Series No. 16, Cardiff, 146pp.

Brooke (1822) Annals of Philosophy, London: 4: 117 (as Cupreous Sulfate of Lead).

Effenberger, H. (1987) Crystal structure and chemical formula of schmiederite, Pb2Cu2(OH)4(SeO3)(SeO4), with a comparison to linarite, PbCu(OH)2(SO4). Mineralogy and Petrology, 36, 3-12.

M. H. Hay, Appendix 1 to the second, edition of an Index of Mineral Species and varities
Arranged Chemically British Museum Natural History, Dec, 1963.
Schmeiderite (p. 84)
"selenate of Pb and Cu [? (Pb, Cu)SeO(OH)] from the Condor mine, La Rioja,
Argentina. Named provisionally by J. Olsacher. Specimen B.M. 1962, 217 (presented by R.
Bideaux) gives an x-ray powder pattern suggesting isotypy with linarite.

Gaines, Richard V., H. Catherine, W. Skinner, Eugene E. Foord, Brian Mason, Abraham Rosenzweig, and Vandall T. King (1997), Dana's New Mineralogy : The System of Mineralogy of James Dwight Dana and Edward Salisbury Dana:

Glocker, E.F. (1839) Handbuch der Mineralogie, 2nd. edition, Nürnberg: 618.

Green, D.I., Rust, S.A. & Mason, J.S., 1996. Classic British mineral localities: Frongoch Mine, Dyfed. UK Journal of Mines & Minerals, 17, 29-38. 

Jones, A.D., 1983. Nant-y-Cagl. Mineral Realm, 3, 42-76.

Mason, J.S. & Green, D.I., 1995. Supergene minerals including exceptional ramsbeckite from Penrhiw Mine, Ystumtuen, Dyfed. UK Journal of Mines & Minerals, 15, 21-27. 

Palache, C., Berman, H., & Frondel, C. (1951), The System of Mineralogy of James Dwight Dana and Edward Salisbury Dana, Yale University 1837-1892, Volume II. John Wiley and Sons, Inc., New York, 7th edition, revised and enlarged, 1124 pp.: 553-555.

Rust, S., 1985. British Micro Localities. No. 12: Esgair Hir Mine (SN 734913), Ceulanymaesmawr, Dyfed, Wales British Micromount Society Newsletter. 13. 13-14. 

Rust, S.A., 1990b. Susannite and sulphatian schmiederite from Llechwedd Helyg Mine, Tir-y-Mynach, Dyfed, Wales. U.K. Journal of Mines and Minerals, 8, 48 

Rust, S.A. & Mason, J.S., 1988. The minerals of Esgair-Hir mine, Dyfed, Wales. UK Journal of Mines & Minerals, 5, 35-43. 

Rust, S. & Rust, D., 1987. Micro-minerals from Dyfngwm Mine. U.K. Journal of Mines and Minerals, No. 2, 28-32. ( This article should be referred to as Dylife mine)

Sowerby, J. (1809) British Mineralogy, or Coloured Figures Intended to Elucidate the Mineralogy of Great Britain. 5 volumes, London: 3: 5, fig. 203 (as Crystallized Blue Carbonate of Copper).