Matlockite is a rare
lead
Lead is a chemical element with the symbol Pb (from the Latin ) and atomic number 82. It is a heavy metal that is denser than most common materials. Lead is soft and malleable, and also has a relatively low melting point. When freshly cu ...
halide mineral
Halide minerals are those minerals with a dominant halide anion (, , and ). Complex halide minerals may also have polyatomic anions.
Examples include the following:
*Atacamite
* Avogadrite (K,Cs)BF
*Bararite (β)
*Bischofite
* Brüggenite ...
, named after the town of
Matlock in
Derbyshire
Derbyshire ( ) is a ceremonial county in the East Midlands, England. It includes much of the Peak District National Park, the southern end of the Pennine range of hills and part of the National Forest. It borders Greater Manchester to the nor ...
, England, where it was first discovered in a nearby mine.
[ Matlockite (chemical formula: PbFCl) gives its name to the matlockite group which consists of rare minerals of a similar structure.
]
Description
The mineral, a lead fluorochloride (formula PbFCl), was discovered sometime around the early 1800s at Bage Mine at Bolehill near Matlock, together with specimens of phosgenite
Phosgenite is a rare mineral consisting of lead chlorocarbonate, (PbCl)2CO3. The tetragonal crystals are prismatic or tabular in habit: they are usually colorless and transparent, and have a brilliant adamantine lustre. Sometimes the crystals ha ...
and anglesite
Anglesite is a lead sulfate mineral with the chemical formula PbSO4. It occurs as an oxidation product of primary lead sulfide ore, galena. Anglesite occurs as prismatic orthorhombic crystals and earthy masses, and is isomorphous with barite and ...
. Although phosgenite was known at this time, it seems likely that matlockite itself remained unappreciated as a new mineral for some fifty years. It was given the name by Greg in 1851. The first mention of Matlockite may have been in Mawe's Mineralogy of Derbyshire in 1802 in which he gives a detailed description of phosgenite, which is then followed by a mention of a mineral he refers to as "glass lead" - a description which does rather equate to the appearance of matlockite. It is a light, translucent creamy-yellow colour, but heavy in weight having a density that is over 7.1.[
A very large specimen 10 cm across, and originating from Derbyshire, exists in the collections of the ]American Museum of Natural History
The American Museum of Natural History (abbreviated as AMNH) is a natural history museum on the Upper West Side of Manhattan in New York City. In Theodore Roosevelt Park, across the street from Central Park, the museum complex comprises 26 inter ...
.[Frondell, Clifford]
American Mineralogist, Vol 20, 469-473, 1935
Retrieved on 2011-01-11 A 7 cm specimen can be found in the collection of Derby Museum and Art Gallery
Derby Museum and Art Gallery is a museum and art gallery in Derby, England. It was established in 1879, along with Derby Central Library, in a new building designed by Richard Knill Freeman and given to Derby by Michael Thomas Bass. The collect ...
.Tiger, Arizona
Tiger is a former populated place in Pinal County in the U.S. state of Arizona. The town was settled as Schultz ''circa'' 1881 in what was then the Arizona Territory, then later reestablished as Tiger after World War I.
History
The area that ...
, Laurium
Laurium or Lavrio ( ell, Λαύριο; grc, Λαύρειον (later ); before early 11th century BC: Θορικός ''Thorikos''; from Middle Ages until 1908: Εργαστήρια ''Ergastiria'') is a town in southeastern part of Attica, Greec ...
in Greece, a mine near Essen
Essen (; Latin: ''Assindia'') is the central and, after Dortmund, second-largest city of the Ruhr, the largest urban area in Germany. Its population of makes it the fourth-largest city of North Rhine-Westphalia after Cologne, Düsseldorf and D ...
in Germany and near Campiglia in Tuscany
Tuscany ( ; it, Toscana ) is a Regions of Italy, region in central Italy with an area of about and a population of about 3.8 million inhabitants. The regional capital is Florence (''Firenze'').
Tuscany is known for its landscapes, history, art ...
. Samples have also been found at locations in South Africa, Peru, Chile, Australia, Austria, France and Italy.[
]
The matlockite group
The matlockite group consists of a number of minerals which share a similar crystal structure. The group includes bismuth, lead or calcium halides: bismoclite
Bismoclite is a bismuth oxohalide mineral with formula BiOCl. It is the naturally occurring form of bismuth oxychloride. The name was derived from its chemical constituents. It is a secondary bismuth mineral first thought to be composed of bismuth ...
, daubréeite
Daubréeite is a rare bismuth oxohalide mineral with formula . It is a creamy-white to yellow-brown, soft, earthy clay–like mineral which crystallizes in the tetragonal crystal system. It is a member of the matlockite group.
It was first desc ...
, laurionite
Laurionite (PbCl(OH)) is a lead halide mineral. It forms colorless to white crystals in the orthorhombic crystal system and is dimorphous with paralaurionite, both members of the matlockite group.
It was first described in 1887 for an occurren ...
, paralaurionite
Paralaurionite is a colorless mineral consisting of a basic lead chloride PbCl(OH) that is dimorphous with laurionite. It is a member of the matlockite group. The name is derived from para-, the Greek for "near", and laurionite, because of its po ...
, rorisite CaFCl, zavaritskite
Zavaritskite is a rare mineral of the halide class, bismuth oxyhalide with the chemical formula (BiO)F. It is named after the Soviet geologist and petrographer, academician of the USSR Academy of Sciences Alexander Nikolaevich Zavaritsky. It was ...
and the eponymous matlockite.
References
External links
{{Derby Museum
Halide minerals
Lead minerals
Tetragonal minerals
Minerals in space group 129
Collections of Derby Museum and Art Gallery
Mixed anion compounds