Ankerite/Ferroan dolomite.

Ankerite/Ferroan dolomite.

Eaglebrook mine, West Wales. Although I have listed this specimen as Ankerite, it may well be Ferroan dolomite. Both of these minerals have been recorded at this mine. The true identity can only be discovered by analytical means.The exposed rhomohedral fracture surfaces have a slight curvature, and the colour varies in shades of brown across the specimen.

Baryte

Baryte

Pen y Clun mine, Central Wales Orefield. Cream coloured massive Baryte composed of compacted bladed crystals in random directions. A few bladed crystals are apparent and well defined in a vugh, indicating the nature of the crystals which make up the specimen as a whole.

Baryte vugh 1

Baryte vugh 1

Bryntail mine, Nr. Llanidloes, Central Wales Orefield. Pinkish, platey crystals of Baryte lining a vugh in a piece of massive Baryte. The other half of the vugh is also in my collection.

Baryte vugh 2

Baryte vugh 2

Bryntail mine, Nr.Llanidloes, Central Wales Orefield. Pinkish, platey crystals of Baryte lining a vugh in a piece of massive Baryte. The other half of the vugh is also in my collection. This is a close up of Baryte vugh 1.

Baryte.

Baryte.

Gorn mine, Nr. Llanidloes, Central Wales Orefield. Massive Baryte with "cockscomb" crystals on the surface.

Baryte.

Baryte.

Bryntail mine, Central Wales Orefield. One half of a Baryte nodule, brken to reveal massive Baryte with a central vugh of small platy crystals. There are also small areas of minute reticulated crystals within the massive body.

Baryte.

Baryte.

Bryntail mine, Central Wales orefield. A solid mass of intergrown bladed crystals. Centrally, the crystals are larger, while those in the lower part are quite small, suggesting that there were different episodes of growth. The Bryntail mine is one of the few mines in central Wales which produced commercial amounts of baryte.

Baryte.

Baryte.

Bryntail mine, Nr Llanidloes, Central Wales orefield. A few specimens recovered from the sorting platform at the remains of the mine. Notice the layered structure, which is not uncommon in specimens from this mine.

Baryte.

Baryte.

Gorn mine, Nr Llanidloes, Central Wales ore field. These specimens were collected from a sorting platform at the old mine workings. They are massive with some cavities containing platy crystals in the cockscomb formation. The larger specimen shows some witherite on the lower right hand side.

Baryte..

Baryte..

Bryntail mine, Nr Llanidloes, Central Wales orefield. A few specimens recovered from the sorting platform at the remains of the mine. Notice the layered structure, which is not uncommon in specimens from this mine.

Brochantite.

Brochantite.

Geufron mine, Central Wales orefield. This sulphate mineral is a secondary mineral of copper, which along with lead was a product of the mine. The specimens were recovered from the spoil heaps at the mine, and are random growths of very small crystalline brochantite embedded in loosely cemented debris.

Calcite

Calcite

Nantiago mine, Central wales Orefield. Calcite displaying typical rhomboid form and cleavage. An abundance of this gangue mineral is to be found at the mine.

Calcite

Calcite

Nantiago mine, Central Wales Orefield. A wedge of Calcite displaying cleavage in three directions, parallel to the rhombohedral form. The two outer faces have a coating about 1mm. thick, grey in colour, and scaly in appearance, sometimes overlapping as in fish scales. Calcite is abundant as a gangue mineral at this mine.

Calcite

Calcite

Nantiago mine, Central Wales Orefield. Two specimens. The first has interleaved flattened scalenahedral crystals with weathered surfaces. The second is mainly composed of massive Calcite adjoining a layer of Sphalerite, in which is embedded a fractured rhombohedral Calcite crystal with a prominent growth line.

Calcite and quartz.

Calcite and quartz.

Nantiera mine, Central Wales orefield. The specimens are predominately calcite in the form of platy crystals. Some of the calcite has been overlain with well defined stubby prismatic crystals of quartz, implying that there have been at least two episodes of mineral deposition at the mine.

Calcite dripstone.

Calcite dripstone.

Siglenlas mine, Central Wales Orefield. A delicate construction of Calcite coating a piece of host rock, unusual in that it has come from a mine rather than a limestone cave.

Calcite.

Calcite.

Llanfawr quarry, Llandrindod Wells. From a fault in the quarry this specimen is nothing out of the ordinary, but interesting because it quite clearly shows the typical Calcite form and cleavage.

Calcite.

Calcite.

Dylife mine, Nr. Staylittle, Central Wales Orefield. Two larger flattened rhombohedral crystals,and a scattering of smaller crystals on a bed of fine druzy Quartz.

Calcite.

Calcite.

Nantiago mine, Central Wales orefield. The bulk of this specimen is massive calcite. One face is covered with bladed crystals. This type of calcite crystal is not very common, and in appearance, the specimen could easily be mistaken for baryte.

Calcite.

Calcite.

Nantiago mine, Central Wales orefield. The uncommonly flat bladed crystals of calcite are deposited on a piece of host rock of indeterminate nature. This type of crystal is more usually associated with barite, which I don't think has been recorded at this mine. The gangue mineral at Nantiago is calcite, and the spoil heaps are littered with the mineral, mostly displaying it's rhombohedral habit.

Calcite.

Calcite.

Nantiago mine, Central Wales orefield. This particular specimen appears to be composed of myriads of very small rhombohedral crystals, many of which are arranged in regimented rows or columns. There are a few small vughs where the construction of the crystals can be better observed, albeit with the aid of a microscope. There are also several small well formed cubes of pyrite inside the vughs.

Calcite.

Calcite.

Creigau quarry, Near Cardiff, South Wales. A collection of twinned scalenahedral crystals of calcite interspersed with much smaller nail head crystals. All the crystals have acquired a coating of a reddy brown colour, probably with an iron content. Close by where this specimen was collected was a five foot cavity in the quarry wall, completely lined with even larger crystals, but impossible to recover without catastrophic damage.

Chalcopyrite.

Chalcopyrite.

Dylife mine spoil heaps, Nr. Staylittle, Central Wales orefield. Although labelled as chalcopyrite, there are also equal amounts of sphalerite and quartz. The chalcopyrite is intermixed with quartz, and varies in colour from gold to bronze. The sphalerite is massive, with just a few obvious crystals, and the quartz is a mass of intergrown crystals. There is also a thin layer of calcite on part of the surface.

Chalcopyrite.

Chalcopyrite.

Siglenlas mine, Nr. Llanidloes, Central Wales ore field. These specimens of brecciated material are typical from this site. Some of the exposed chalcopyrite not yet weathered, displays the usual pale brassy colour. The specimens are made up of quartz, host rock, and chalcopyrite. I estimate the chalcopyrite content to be between five and ten percent, which would have made the processing economically viable.

Chalopyrite.

Chalopyrite.

Geufron mine, Central Wales orefield. A nugget of massive chalcopyrite with a fractured face displaying the usual pale yellow colour. The rest of surface of the specimen has weathered and taken on the green colour of copper exposed to air. The chalcopyrite does not have any discernible crystals and is intermixed with a minor amount of quartz and very small pieces of host rock.

Chrysocolla 1

Chrysocolla 1

Geufron mine, Central Wales Orefield. Specimens collected from the spoil heaps at the mine. Specimens are abundant and are from the surface or just below. The encrustations are mostly without detail, but sometimes include small areas of globular growth. The encrustations are believed to be Chrysocolla, but will need X-ray diffraction to verify.

Chrysocolla 2

Chrysocolla 2

Geufron mine, Central wales Orefield. Detail enlargement from Chrysocolla 1. The globular nature of some of the encrustation is more apparent. The adjacent mine of Hafod Feddgar has an adit with a very large area of encrustation on both walls and floor which is very similar in appearance.

Copper staining.

Copper staining.

Hafod Feddgar mine, Central Wales orefield. The mine, having been closed for about 100 years, has given time for copper solution to stain leached calcite on the walls and floor of the adit. Not wishing to disturb the main body of interest, this specimen was taken from the floor close by. It is brecciated rock with precipitated calcite on the surface, coloured by copper solution leaching from the roof.

Dolomite / Quartz

Dolomite / Quartz

Tan y Foel quarry, Cefn Coch, Nr Welshpool, Central Wales. The quarry provides a section through the Wenlock, mid Silurian, sedimentary deposits. The rocks belong to the Penstrowed grits fm. The specimen is an example of material from the occasional fault within the quarry, and shows veins filled with Dolomite and Quartz. A small vugh has allowed the growth of clear Quartz crystals and numerous tiny Dolomite crystals which display the familiar curved faces.

Dolomite / Quartz

Dolomite / Quartz

Penstrowed quarry, Newtown, Central Wales. This specimen is very similar to another which was collected from a quarry at Cefn Coch, several miles away. Both quarries are in the Penstrowed grits fm, a mid Silurian sedimentary deposit. The rock has several vughs of quartz crystals, and dolomite crystals, both of which are very sharp and well formed.

Dolomite.

Dolomite.

Bryntail mine, Central Wales orefield. It is unusual to find such a well formed specimen of dolomite in the central Wales orefield. It is more usual to find ferroan dolomite. The specimen has a very uniform construction and the curved surface and rhombohedral habit is very obvious. The colour is greyish white and there is no sign of brown or other colours in this and other similar specimens found on the mine spoil heaps.

Druzy Quartz

Druzy Quartz

Van mine, Central Wales Orefield. Clusters of small, very fine, well formed Druzy Quartz crystals. The crystals are clear, and only observable under high magnification.

Druzy Quartz and Calcite 1

Druzy Quartz and Calcite 1

Dylife mine, Central Wales Orefield. Clear druzy Quartz crystals with a uniform size of about 1mm. on the front and rear of a piece of host rock. There are several small deposits of Calcite on top of the druzy Quartz. The Quartz and Calcite were deposited from hydrothermal circulating fluids at depth with the Quartz being deposited first. Finer detail of the Calcite is to be seen in Druzy Quartz and Calcite 2.

Druzy Quartz and Calcite 2.

Druzy Quartz and Calcite 2.

Dylife mine, Central Wales Orefield. Detail from Druzy Quartz and Calcite 1. Although the deposits are very small, the cleavage and rhombohedral structure of the Calcite is well observed.

Ferroan Dolomite

Ferroan Dolomite

Dylife mine, Central Wales Orefield. An off white aggregate with typical curved faces on the exposed fracture surface. The host rock on which it is deposited is a brecciated light coloured sandstone. Layering observed in the Dolomite indicates that this is a vein fragment.

Galena and quartz.

Galena and quartz.

Nantiera mine, Central Wales orefield. Broken galena crystals in a bed of druzy quartz, deposited in a fractured host rock There are also minor amounts of chalcopyrite.

Galena on Quartz.

Galena on Quartz.

Dylife mine, Nr. Staylittle, Central Wales Orefield. Pieces of brecciated material with a very fine coating of druzy Quartz, on which are scattered flattened crystals of Galena.The base rock is very light grey in colour.

Galena with quartz.

Galena with quartz.

Aberdaunant mine, Nr. Llanidloes, Central Wales ore field. Collected from spoil heaps at the mine, these specimens are a galena- quartz breccia The quartz is massive with no sign of crystals. The galena is also massive with just a small indication of a few small broken crystals, which display the natural cleavage planes. As is often the case in this area, some of the exposed broken surfaces have a bright blue sheen.

Galena.

Galena.

Eaglebrook ( Nantycagl ) mine, Nant y moch res. West Wales. Small platelets of Galena grown on a thin bed of extremely fine druzy Quartz.The bed continues under the small piece of the remaining attached rock indicating that this was once a very narrow vein within the rock.

Galena.

Galena.

Pen Dylife mine, Nr Staylittle, West Wales. Thin deposits of galena occupying faults in fractured host rock. There are no complete crystals in the specimins, but the typical galena cleavage is observed in the exposed fracture surfaces. These specimins were recovered from the wall of a long abandoned open cut excavation.

Galena.

Galena.

Pen y Gaer hill, Llanidloes, Central Wales ore field. This specimen was obtained from a very small trial, not known as a mine. It is about 80% galena with the rest being quartz. The galena is very finely cleaved and is better observed under a microscope. The quartz is a very fine aggregate intermixed with galena.

Goethite

Goethite

Aberdaunant mine, Central Wales Orefield. Two, very thin deposits of Goethite on a piece of host rock. The first deposit is pisolitic in nature, and is overlain by the second deposit which is in the form of an encrustation. The encrustation is removed here and there exposing the pisolitic first deposit.

Goethite on Pyrite.

Goethite on Pyrite.

Aberdaunant mine, Central Wales Orefield. Fractured country rock with small cubic Pyrite crystals and Quartz. Most of the Pyrite crystals are encrusted with Goethite which is common at this site.

Goethite.

Goethite.

Aberdaunant mine, Nr. Llanidloes, Central Wales ore field. An encrustation with no visible crystals on brecciated rock of quartz and host rock. The goethite is slightly mammillary in appearance in places.

Hematite

Hematite

Aberdaunant mine, Central Wales Orefield. The host rock appears to be brecciated sandstone. The Hematite, which is deposited on the surface is botryoidal in nature, albeit on a very small scale, and there are a few areas of iridescence, gold and silver in appearance. Also on the specimen is a small area encrusted with numerous very small brown crystals of Quartz.

Hematite.

Hematite.

Dylife mine, Nr. Staylittle, Central Wales orefield. This rather weighty specimen is obviously a small part of a much larger original formation. There are obvious signs of a radiating construction on the reverse. The surface texture is made of indistinct crystals, possibly the terminations of a radial growth. The specimen is non-magnetic, implying that there is no magnetite present.

Hemimorphite. 1

Hemimorphite. 1

Henfwlch mine, West wales. The beauty of the hemimorphite crystals in these specimens can only he appreciated under a microscope. The Henfwlch mine is noted for the presence of hemimorphite, which is a zinc ore found in the weathering zones of sphalerite deposits. see hemimorphite. 2 for more specimens.

Hemimorphite. 2

Hemimorphite. 2

Henfwlch mine, West Wales. When these specimens of hemimorphite are observed under the microscope sprays of radiating bladed clear crystals can be seen. Also common at this mine are microcrystalline globules which can just about be seen in the centre left pocket, and the top and bottom right pockets. When I can arrange it I will update this entry with better photographs. Each pocket measures 6cm. by 4.5cm.

Hydraulic brecciation.

Hydraulic brecciation.

Bryn y Rafr mine, West Wales. Typical brecciated material from this site, which is a mix of host rock, Quartz, and Sphalerite. The host rock is a fine grained dark mudstone. Brecciation is the result of inwardly exploding walls of deep fractures when there is a sudden decrease of pressure in the hot mineral rich fluids which are circulating through the fracture.

Hydraulic brecciation.

Hydraulic brecciation.

Cafartha mine, Staylittle, Central Wales ore field. This pretty little specimen is a mix of host rock, with precipitated quartz, some of which is druzy and lining small cavities. There are also very minor amounts of galena on the surface. Brecciation is the result of inwardly exploding walls of deep fractures when there is a sudden decrease of pressure causing shards of wall rock to be injected into the hot mineral rich fluids which are circulating through the fracture.

Hydraulic brecciation.

Hydraulic brecciation.

Castell mine, West Wales. This fine example of hydraulic brecciation is made up of host rock, quartz, and ferroan dolomite. The brecciation is the result of inwardly exploding walls in deep fractures. A sudden decrease of pressure causes shards of wall rock to be injected into the hot mineral rich fluids which are circulating through the fracture. Larger pieces of the ferroan dolomite can easily be found on the spoil heaps at this long abandoned mine. Along with quartz, the ferroan dolomite would be considered as one of the gangue minerals at the mine.

Hydrozincite.

Hydrozincite.

Pencurig mine, Dylife, Central Wales ore field. The specimens were recovered from the floor of an adit, perhaps taking about 100 years to form since closure of the mine. Hydrozincite is also known as zinc bloom or marionite, and is a zinc carbonate. These specimens have a substantial coating, which is very white, and vitreous in appearance.

Linarite and Malachite.

Linarite and Malachite.

Geufron mine, Central Wales Orefield. Quartz rich host rock with an encrustation of Malachite overlying deep blue Linarite. Most of the Linarite is an encrustation in the form of tightly compacted crystals. Several radiating sprays of bladed crystals about .5mm. in length can be seen with high magnification.

Marcasite

Marcasite

Bryn y Rafr mine, West Wales. Two halves of a broken specimen. The Marcasite is in massive form with no crystals apparent, and with a pale yellow colour. This mineral is very susceptible to "Pyrite decay" and the specimen is kept in a sealed plastic box with a plentiful supply of Silica sachets.

Marcasite / Quartz

Marcasite / Quartz

Bryn y Rafr mine, West Wales. Country rock with Quartz and Marcasite content. The Marcasite has suffered from "Pyrite decay", breaking down into Sulphuric acid and Hydrous Iron Sulphate, the light coloured deposit on the surface.

Marcasite / Quartz

Marcasite / Quartz

Bryn y Rafr mine, West Wales. This brecciated rock is a mixture of host rock, quartz, and marcasite. Unfortunately marcasite is prone to pyrite decay, and this is well illustrated on this specimen. The marcasite has broken down resulting in an encrustation of sulphur. The process has been treated and almost stopped by storing in an airtight box and surrounded with a liberal supply of silica desiccant pouches. The rock itself is very fragile with cracking apparent, probably because of marcasite content. The same can be said of the quartz, which is also very fragile.

Marcasite and quartz.

Marcasite and quartz.

Bryn y Rafr mine, West Wales. Alternating layers of marcasite and quartz. The marcasite is subject to pyrite decay, hence the yellow sulphurous deposits. The quartz shows very little evidence of crystals, instead it appears as though it has flowed over the marcasite.

Marcasite/Quartz

Marcasite/Quartz

Bryn y Rafr mine, West Wales. A layer of Marcasite, sandwiched between two layers of badly defined druzy Quartz, one layer with much smaller crystals. The Marcasite has suffered Pyrite decay, hence the sulphurous deposits on the surface. Although the specimen is kept in a sealed box with Silica dessicates to halt the decay, a steel label, also in the box is very badly rusted by the chemical reaction.

Mineral assemblage on host rock.

Mineral assemblage on host rock.

Aberdaunant mine, Central Wales Orefield. A deposition of different minerals on two faces of host rock. Fine crystals of Quartz, Fine botryoidal Hematite, and a very small amount of Galena. This type of specimen is not uncommon at Aberdaunant mine.

Pyrite on Dolomite

Pyrite on Dolomite

Tan y Foel quarry, Nr Adfa. Central Wales. Minute cubic crystals of pyrite deposited on larger cubic crystals of dolomite. Two groups of crystals,some are brassy yellow and definitely pyrite, and some are almost black and possibly magnetite.

Pyromorphite

Pyromorphite

Aberdaunant mine, Central Wales Orefield. Apple green, barrel shaped crystals, scattered haphazardly on a base rock which is liberally coated with a mixture of Quartz, Galena, and Goethite/Hematite. Pyromorphite is also found at this mine in globular form, or as encrustations.

Pyromorphite

Pyromorphite

Aberdaunant mine, Central Wales Orefield. Apple green in a globular habit with a sub-columnar structure. The base rock is coated with a mixture of Quartz, Galena, and Goethite/Hematite. Pyromorphite is also found at this mine as small barrel shaped crystals, and as encrustations.

Pyromorphite.

Pyromorphite.

Bwlch Glas mine, Nr. Talybont, West Wales. Some stubby, some elongated, barrel shaped crystals. Colouration mostly light to dark green, but with a few almost colourless crystals.

Quartz

Quartz

Dyife mine Nr Staylittle,Central Wales Orefield. Miscellaneous specimens of Brecciated material, with small Quartz crystals and Druzy Quartz filling the crevices. Collected for simply being"pretty" specimens.

Quartz crystals.

Quartz crystals.

Van mine, Central wales orefield. These specimens were picked up many years ago, before "landscaping" removed all traces of mine waste. Today it would be almost impossible to find any mineral specimens from what was the largest mine in central Wales. The crystals are prismatic and of the milky quartz variety. The specimen with then larger and less distinct crystals has a slight surface discolouration due to iron staining.

Quartz crystals.

Quartz crystals.

Llawr y Glyn, Nr. Staylittle, Central Wales. This unremarkable specimen is included in my collection simply because it was one of my earliest collected specimens over twenty years ago. The specimen simply fell out of a roadside embankment, unusual because the nearest mine workings are about two miles distant, perhaps indicative of an undiscovered mineral lode close by.

Quartz in brecciated rock.

Quartz in brecciated rock.

Bryn Y Rafr mine, West Wales. Common in Hydrothermal ore deposits, brecciated rock is produced by means of hydraulic brecciation. The walls of host rock within fissures is fractured because of changing pressures in hot circulating mineral rich fluids, and is mixed with minerals precipitating from the fluids as it cools,In this instance Quartz.

Quartz miscellaneous.

Quartz miscellaneous.

Bryn y Rafr mine, West Wales. The two smaller specimens are skeletal in appearance, because the mineral which once occupied the cavities has weathered out. There are remnants of marcasite in a few places, and in the upper specimen there are numerous small cavities where impressions of the weathered mineral are well defined. The larger specimen is an example of crystal growth outwards from the two walls of a crevice or vein and meeting in the centre.

Quartz, Druzy var.

Quartz, Druzy var.

Bryn y Rafr mine, Central Wales Orefield. A specimen composed of Druzy Quartz, with a small surface deposit of Hematite. The composition implies that this was a brecciation out of which the host rock has been removed by weathering. The Hematite is minimal and appears to be a later deposition.

Quartz, Druzy var.

Quartz, Druzy var.

Eaglebrook mine, West Wales. A fine example of druzy quartz. Although druzy quartz is not uncommon and not of particular scientific interest, this specimen with its well formed stubby prismatic crystals proved to be too nice to leave on the spoil heaps.

Quartz, Druzy var.

Quartz, Druzy var.

Bryn y Rafr mine, West Wales. There is nothing unusual or spectacular about this specimen. I have included it simply because it is part of my collection. This is a vugh of minute dark coloured druzy quartz crystals no more than a quarter of a millimetre in size. There is a small amount of lighter coloured quartz around the edges of the vugh.

Quartz, Druzy var.

Quartz, Druzy var.

Cafartha mine, Nr. Staylittle, Central Wales ore field. This specimen, though small, is among my favourites. It was obtained very carefully from the roof of an adit which was on the point of collapse, and in fact did collapse a few days later. The crystals are pin sharp and well formed, with a light coating of iron staining. The underside is very reddish brown and is obviously iron rich.

Quartz, Hematitic var.

Quartz, Hematitic var.

Aberdaunant mine, Central Wales orefield. Small prismatic crystals in druzy form, with varying degrees of hematitic colouration, from pale red to yellowish brown.

Quartz, Hematitic var.

Quartz, Hematitic var.

Dyfyngwm mine, Nr.Staylittle,Central Wales. Brecciated rock with a vhug of small druzy crystals of Quartz which have been coloured by Hematite.

Quartz, Hematitic variety.

Quartz, Hematitic variety.

Bryn y Rafr mine, West Wales. Very small druzy crystals of quartz in host rock which has been coloured red by iron. The crystals are well formed, and are deep red in colour. The specimens have no trace of other minerals.

Quartz, Net veining.

Quartz, Net veining.

Bryn y Rafr mine, West Wales. An example of net veining on a small scale. The host rock does seem to be composed of two slightly different rocks. The difference in composition would encourage net veining, which in this case is quartz veining. There is a small area of very fine druzy quartz on the surface.

Quartz, Unclassified.

Quartz, Unclassified.

Pencurig mine, Dylife, Central Wales ore field. These specimens were taken from the wall of an adit. I have labelled them as unclassified because of their peculiar nature. The Quartz appears to be fractured and friable, and can be easily broken by hand. Friable quartz can be found as a sedimentary deposit, but this quartz is from a hydrothermal source.

Quartz.

Quartz.

Ystrad Meurig quarry, Ysbyty Ystwyth, West Wales. Dirty white prismatic crystals of Milky Quartz in a cluster, growing at random angles to the base rock which is a very roughly formed Quartz aggregate. Some of the crystals taper slightly toward the base.

Quartz.

Quartz.

Cwm Fron mine, Nr. Tylwych, Central Wales. At first glance this seam fragment appears to be Calcite, but on testing and closer inspection,it is Quartz. Very irregular intergrown prismatic crystals, some with darkened cores.

Quartz.

Quartz.

Bryn y Rafr mine, West Wales. Two specimens of poorly defined quartz crystals, which appear to have grown into a cavity from the rock wall. The specimen in the centre could be described as "skeletal" quartz because minerals which were once embedded in the quartz have weathered out leaving numerous small cavities. There are also a few sugary deposits of quartz, with no well defined crystals. This type of specimen is very common on the mine spoil heaps.

Quartz.

Quartz.

Aberdaunant mine, Nr. Llanidloes, Central Wales ore field. This specimen is included in my collection because it is representative of many similar pieces found on the spoil heaps. There are some well formed crystals, but most of the quartz is irregular and mis-shapen. There is some iron staining on most of the specimen.

Siderite

Siderite

Ystrad Meurig quarry, Ysbyty Ystwyth, West Wales. A saddle shaped aggregate, cream in colour. No crystals are found on this specimen, but rhombohedral cleavage is apparent on the fractured surface.

Siderite 1.

Siderite 1.

Castell mine, West Wales. A concretionary mass of small rhomohedral crystals. The crystals have curved, striated faces, and vary in colour from pale cream to light brown.

Siderite 2.

Siderite 2.

Castell mine, West Wales. A small vugh of rhombohedral Siderite crystals on a different face of the specimen in Siderite 1. The crystals have an almost imperceptible curved face, and very faint striations.

Siderite.

Siderite.

Cafartha mine, Nr Staylittle, Central Wales ore field. This brecciated material is mostly siderite with small pieces of host rock, and a small amount of calcite. The siderite, which is an iron-carbonate is very pale brown in colour, with a slight curvature on exposed surfaces. There are no actual crystals on any of the specimens.

Siderite.

Siderite.

Van mine, Nr. Llanidloes, Central Wales ore field. This brecciated specimen is a mix of host rock, quartz, and siderite. The quartz, which is a gangue mineral at this mine is of a "sugary" nature, with no crystals to be seen. The siderite is not so solid as seen at other mines locally, but seems to be granular in nature, with just enough crystals to identify the mineral.

Siderite.

Siderite.

Aberdaunant mine, Nr. Llanidloes, Central Wales ore field. This specimen is brecciated material, composed of calcite, host rock, and siderite, more properly known as iron-carbonate. The bulk of the specimen is siderite, with just enough of it's slightly curved rhombohedral nature to allow identification. An old fashioned name for siderite is chalybite, and there are records of chalybeate springs in central wales.

Siderite.

Siderite.

Siglenlas mine, Nr. Llanidloes, Central Wales ore field. There is very little left in the way of spoil heaps at this location, so to find this particular specimen was extremely fortunate. The rock is brecciated with pockets filled with siderite. One face is completely covered with siderite, with a bunch of well formed crystals in the centre. The crystals, even if they are very weathered, make identification much easier.

Spalerite 3.

Spalerite 3.

Dylife mine,Central Wales orefield. The sphalerite is massive,with no discernable individual crystals,and enclosing one or two shards of original host rock,indicating an earlier episode of hydraulic brecciation. Also in the specimens is an equal amount of quartz,which does have intergrown crystals,albeit not very well defined, which suggests that the quartz grew into cavities after the original brecciation. Also observed on the surface are a few small deposits of galena,and a vey small deposit of chalcopyrite.

Sphalerite

Sphalerite

Dylife mine, Central Wales Orefield. Brecciated rock from ore deposits, consisting of light grey country rock, possibly limestone with Sphalerite in massive form. Also very fine druzy Quartz and very minor Galena. The Sphalerite is overlying the Quartz in several places, indicating that the Sphalerite was a later deposit.

Sphalerite

Sphalerite

Dylife mine, Central Wales Orefield. Sphalerite in massive form with apparent alignment features. The Sphalerite, which is almost black may have derived it's colour from the presence of Iron.

Sphalerite / Quartz.

Sphalerite / Quartz.

Bryn y Rafr mine, West Wales. Several layers of Sphalerite separated by Quartz. There are no observable crystals in the Sphalerite or the Quartz. The Quartz has reddish staining, which is probably Iron staining.

Sphalerite and siderite

Sphalerite and siderite

Castell mine, West Wales. The bulk of the specimen is massive siderite with just the odd observable crystal. The sphalerite is randomly distributed in small pockets, and in a few places the very deep red colour of sphalerite can be seen.

Sphalerite,Galena and Calcite.1

Sphalerite,Galena and Calcite.1

Nantiago mine, Central wales Orefield. Sphalerite and Galena filling crevices in fractured Calcite. The Sphalerite is a coarse aggregate with a very deep red colouration, and the Galena is mostly in the form of cubo-octahedral crystals. The ratio is approximately 90% to 10% in favour of the Sphalerite.

Sphalerite,Galena and Calcite.2

Sphalerite,Galena and Calcite.2

Nantiago mine, Central Wales Orefield. This is a detail from Sphalerite, Galena, and Calcite 1. The Galena cubo-octahedral crystals are in the lower half of the photograph, and the Sphalerite aggregate is in the upper half.

Sphalerite.

Sphalerite.

Cwmbryno mine, West wales. Sphalerite in brecciated rock. An aggregate of the zinc sulphide, with no well defined crystals. There is a coating of fine druzy quartz on one surface, and also some iron staining. This type of specimen is typical of many to be found on lead mine spoil heaps.

Witherite.

Witherite.

Gorn mine, Nr. Llanidloes, Central Wales Orefield. Small pieces of Witherite, possibly fragments of much larger pieces. The specimens are translucent, and dark cream in colour with no definite crystals observed. However there are parallel growth lines on most pieces found. The specimens were collected from an overgrown sorting floor at the mine.