In this article we link the minerals to be found on Grassington Moor to the potential impact on the health of the miners and their families. Modern uses of each mineral are also suggested.
In 1851 Queen Victoria opened the Great Exhibition in the Crystal Palace in Hyde Park, a building designed by Joseph Paxton, who had constructed the Great Conservatory at Chatsworth for the Duke of Devonshire. Amongst the 100,000 objects on display there were two from the Grassington area, reflecting the ties with the Duke:
- Classes 12 & 15 Woollen and Worsted
159 Wall, Cockshot 7 Wall, Linton Mills, near Skipton.
– Shaded tapestry ground, with silk figure, shot and printed ground Orleans &c. Preparation of Worsted Yarn; - Class 1 Mining and Mineral Products
496 Devonshire, The Duke of, and his agent, Captain Eddy, Grassington.
– Specimen of Devonshire lode, grit stone &c Transverse sections of the Devonshire lode.
The mineral specimen is shown in the first plate in a book: “Geology of the Northern Pennine Orefield” Vol. 2, Stainmore to Craven, 1985, K.C. Dunham and A.A. Wilson. The description says a “section of a lead vein from Grassington High Moor, presented by His Grace the Duke of Devonshire to the 1851 Exhibition and now displayed in the Geological Museum London SW7. Bands of Galena alternate with fluorite and baryte. Width of vein 0.35m.
The Geological museum is now part of the Natural History Museum (www.nhm.ac.uk), so it would be interesting to look for the specimen in their mineral collection. A search for “Grassington” reveals some fascinating results for us, if not toxic results for miners.
In the following sections, the description and donor text are provided by the Natural History Museum. However the text and images are taken from wikipaedia or geology websites, so if members can help with any more specific information, it would be appreciated. The “11 most dangerous minerals” is taken from www.mining-technology.com.
Galena and Slickensides Galena
Gallena Slickenside
Donor: Capt. S Eddy, the Duke’s Mineral Agent
Description: Veins in Sandstone
On the list of 11 most dangerous minerals
Galena is the natural mineral form of Lead Sulfide, which when smelted, produces lead and sulphur dioxide, a toxic gas that smells of burnt matches. Sulfur dioxide combined with moisture in the air forms sulfuric acid which is a contributor towards acid rain. The smell and the effect on the nearby moorland are some of the reasons why the chimney on Grassington Moor is a significant distance down wind from the Cupola Smelt mill.
Galena is used as a green glaze in pottery. It was also used in the eye cosmetic kohl, which was applied round the eyes in Ancient Egypt.
For miners Galena Slickenside is a dangerous rock. A blow with a hammer, a stroke or a scratch with a miner’s pick are sufficient to cause an explosion. The stroke is immediately succeeded by a crackling noise and then the explosion.
Cinnabar and Metacinnabar
Cinnabar
Donor: AWG Kingsbury
Description of Cinnabar assets:
- Compact earthy from a pocket of red clay in oxidised vein material
- Earthy in cavities in galena-fluorite-veinstone; with cerussite, anglesite, etc
- Red earthy on galena-fluorite matrix; with cerussite, etc
- Small bright-red crystal on grit
- Red crystalline on baryte, Red earthy on baryte; with a small plate of amalgam and Red earthy on grit; with earthy Iron oxides
On the list of 11 most dangerous minerals
Cinnabar is a toxic mercury sulfide mineral and is the only important ore of mercury. It has a bright red colour that has caused people to use it as a pigment and carve it into jewellery and ornaments for thousands of years in many parts of the world.
However, smelting of the ore produces sulfur dioxide and mercury vapour. Mercury and its vapour were used as medical treatments, including amalgam for tooth fillings, until it was realised that the vapour caused symptoms such as tremours, mood swings, irritability, nervousness and excessive shyness.
There are three other types of mercury mineral listed in the Natural History Museum Collection for Grassington:
- Metacinnabar – Minute grey-black tetrahedra on calcite crystals on matrix; with cinnabar;
- Mercury – Minute globules in cavities in oxidised ‘gossany’ matrix; with calomel, malachite;
- Calomel – Grey transparent crystals in cavities in oxidised ‘gossany’ matrix; with mercury, malachite.
Malachite is a green calcium carbonate mineral.
Metacinnabar
Sphalerite
Sphalerite
This is the chief ore of zinc and is often found with Galena. Miners have been known to refer to it as zinc blende, Black Jack or Ruby Jack. It is another sulphide and sometimes contains iron which may explain some of the rusty coloured areas on the Moor.
It has been used as a gemstone but is not suitable for setting. It can contain trace elements, such as cadmium, gallium, germanium and indium. The use of cadmium in batteries is now banned by the EU as it is linked to liver failure, whilst the other three are used in the electronics industry as semi conductors.
Rosasite and Smithsonite
Rosasite
Donor: AWG Kingsbury
Description:
- Rosasite: Crust of minute green spherules on smithsonite
- Smithsonite: Yellowish-brown to grey botryoidal massive
Smithsonite
Rosasite is a mineral containing Zinc and Copper. Neither are toxic at normal levels. Zinc contributes to the normal function of the immune systems and copper helps make red blood cells. Both can be bought as dietary supplements.
Smithsonite mineral is similar to Rosasite and contains Zinc. It is used in calamine lotion which is on the World Health Organisations list of Essential Medicines. It is also used as gemstone Bonamite.
Cerrusite
Donor: AWG Kingsbury
Description:
- Orange-red crystals and massive in cavities in matrix
- Orange-red compact in veins in baryte
Cerussite is a lead carbonate mineral, usually found in the oxidized zone of lead ore deposits. It is a very common weathering product of galena and other lead ore minerals.
It was the lead used in lead paints and ingestion of lead based paint chips was the most common cause of lead poisoning in children. Cerrusite was also used in cosmetics.
Cerrusite
Barytes
Barytes
Reworking of spoil heaps in the Moor in the 1950s and 60s by the Dales Chemical Company was a commercial attempt to extract the Barytes as this had been done successfully at Connonley.
Barium sulfate was used as a white pigment in paints and is still used in glass ceramics, barium meals and friction products in the gas exploration and motor industries.
Fluorspar
Donor: T Eastwood
On the list of 11 most dangerous minerals
Fluorine is a relatively soluble mineral contained in Fluorite and can lead to a severe bone disease called skeletal fluorosis.
Fluorite is used in ornaments and jewellery as well as a flux for smelting glass.
Fluorspar
Other minerals in the collection
Apatite – Used in manufacture of fertilisers.
Aragonite – A naturally occuring crystal of calcium carbonate used for the removal of pollutants like zinc, cobalt and lead from contaminated wastewaters.
Crandallite – A calcium aluminium basic phosphate mineral. The Grassington exhibit is a “Greenish-yellow layered aggregate”.
Jarosite – A sulphate of potassium and iron often associated with acid mine drainage.
Parahopeite – A hydrated zinc phosphate. It is a rare mineral used mainly as a collectors specimen.
Spencerite – A zinc phosphorous mineral. The Grassington exhibit is described as “Aggregates of pearly bladed crystals in subparallel position”.
Lastly, these minerals are taken straight from the collection:
- Blende xld w. calcite on sandstone;
- Breccia grit cemented with Galena and Zinc Blende;
- Calcerous grit;
- Sandy limestone;
- Bituminous limestone;
- Calcite.
Keith Parker
