Matlockite

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Matlockite
Matlockite-190524.jpg
General
Category Halide minerals
Formula
(repeating unit)		PbFCl
IMA symbol Mtl [1]
Strunz classification 3.DC.25
Dana classification 9.2.11.1
Crystal system Tetragonal
Crystal class Ditetragonal dipyramidal (4/mmm)
H-M symbol: (4/m 2/m 2/m)
Space group P4/nmm
Unit cell a = 4.11 Å, c = 7.23 Å; Z = 2
Identification
ColourColourless to yellow and greenish
Crystal habit Flattened, tabular crystals occurring as aggregates, rosettelike, radiating, hemispherical; also massive
Cleavage {001}, perfect
Fracture Uneven to subconchoidal
Tenacity Brittle
Mohs scale hardness2.5 – 3
Luster Adamantine, pearly on {001}
Diaphaneity Transparent
Specific gravity 7.1 – 7.2
Optical propertiesUniaxial (−)
Refractive index nω = 2.150 nε = 2.040
References [2] [3] [4]

Matlockite is a rare lead halide mineral, named after the town of Matlock in Derbyshire, England, where it was first discovered in a nearby mine. [3] Matlockite (chemical formula: PbFCl) gives its name to the matlockite group which consists of rare minerals of a similar structure.

Contents

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 and anglesite. 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. [5] The first mention of matlockite may have been in Mawe's Mineralogy of Derbyshire in 1802 [6] 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. [4]

A very large specimen 10 cm across, and originating from Derbyshire, exists in the collections of the American Museum of Natural History. [7] A 7 cm specimen can be found in the collection of Derby Museum and Art Gallery. [8]

Matlockite has been reported from a variety of locations since its discovery at the type locality of Derbyshire. The mineral is also found in Tiger, Arizona, Laurium in Greece, a mine near Essen in Germany and near Campiglia in Tuscany. Samples have also been found at locations in South Africa, Peru, Chile, Australia, Austria, France and Italy. [3] [4]

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 (BiO)Cl, daubréeite (BiO)(OH,Cl), laurionite PbCl(OH), paralaurionite PbCl(OH), rorisite CaFCl, zavaritskite (BiO)F and the eponymous matlockite. [9]

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6O
8−x(Cl,Br)
2x (x ≤ 0.5).

<span class="mw-page-title-main">Phosgenite</span>

Phosgenite is a rare mineral consisting of lead carbonate chloride, (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 have a curious helical twist about the tetrad or principal axis. The hardness is 3 and the specific gravity 6.3. The mineral is rather sectile, and consequently was earlier known as corneous lead, (German Hornblei).

<span class="mw-page-title-main">Bolehill, Derbyshire</span> Human settlement in England

Bolehill is an area of Wirksworth, Derbyshire, England. It is located in the north of the town and has connections to the lead mining. Bolehill is adjacent to Black Rocks, a local landmark and a short walk from the High Peak Trail at Middleton incline.

<span class="mw-page-title-main">John Mawe</span>

John Mawe was a British mineralogist who became known for his practical approach to the discipline.

<span class="mw-page-title-main">Halide mineral</span> Minerals with a dominant fluoride, chloride, bromide, or iodide anion

Halide minerals are those minerals with a dominant halide anion. Complex halide minerals may also have polyatomic anions.

<span class="mw-page-title-main">Duftite</span> Arsenate mineral

Duftite is a relatively common arsenate mineral with the formula CuPb(AsO4)(OH), related to conichalcite. It is green and often forms botryoidal aggregates. It is a member of the adelite-descloizite Group, Conichalcite-Duftite Series. Duftite and conichalcite specimens from Tsumeb are commonly zoned in color and composition. Microprobe analyses and X-ray powder-diffraction studies indicate extensive substitution of Zn for Cu, and Ca for Pb in the duftite structure. This indicates a solid solution among conichalcite, CaCu(AsO4 )(OH), austinite, CaZn(AsO4)(OH) and duftite PbCu(AsO4)(OH), all of them belonging to the adelite group of arsenates. It was named after Mining Councilor G Duft, Director of the Otavi Mine and Railroad Company, Tsumeb, Namibia. The type locality is the Tsumeb Mine, Tsumeb, Otjikoto Region, Namibia.

<span class="mw-page-title-main">Boleite</span>

Boleite is a complex halide mineral with formula: KPb26Ag9Cu24(OH)48Cl62. It was first described in 1891 as an oxychloride mineral. It is an isometric mineral which forms in deep-blue cubes. There are numerous minerals related to boleite, such as pseudoboleite, cumengite, and diaboleite, and these all have the same complex crystal structure. They all contain bright-blue cubic forms and are formed in altered zones of lead and copper deposits, produced during the reaction of chloride bearing solutions with primary sulfide minerals.

<span class="mw-page-title-main">Bismoclite</span>

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 bismuthyl ions (BiO+) and chloride anions, however, the existence of the diatomic bismuthyl ion is doubtful.

<span class="mw-page-title-main">Bismuth oxychloride</span> Chemical compound

Bismuth oxychloride is an inorganic compound of bismuth with the formula BiOCl. It is a lustrous white solid used since antiquity, notably in ancient Egypt. Light wave interference from its plate-like structure gives a pearly iridescent light reflectivity similar to nacre. Previously, until the last decade of the twentieth century, bismuth oxochloride was known as bismuthyl chloride. It is also known as pigment pearl white.

<span class="mw-page-title-main">Plumbogummite</span> Alunite supergroup, phosphate mineral

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<span class="mw-page-title-main">Laurionite</span>

Laurionite 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.

<span class="mw-page-title-main">Paralaurionite</span>

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 polymorphic relationship to it. Bright, yellow tips of thorikosite can form on paralaurionite crystals and paralaurionite may also be intergrown with mendipite.

<span class="mw-page-title-main">Tarbuttite</span> Phosphate mineral

Tarbuttite is a rare phosphate mineral with formula Zn2(PO4)(OH). It was discovered in 1907 in what is now Zambia and named for Percy Coventry Tarbutt.

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Diaboleite is a blue-colored mineral with formula Pb2CuCl2(OH)4. It was discovered in England in 1923 and named diaboleite, from the Greek word διά and boleite, meaning "distinct from boleite". The mineral has since been found in a number of countries.

Daubréeite is a rare bismuth oxohalide mineral with formula BiO(OH,Cl). 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.

<span class="mw-page-title-main">Mammothite</span>

Mammothite is a mineral found in the Mammoth mine in Tiger, Arizona and also in Laurium, Attika, Greece. This mineral was named in 1985 by Donald R. Peacor, Pete J. Dunn, G. Schnorrer-Köhler, and Richard A. Bideaux, for the Mammoth vein (one of the two main veins in the mine) and the town of Mammoth, Arizona, which was named for the mine. The mammothite that is found in Arizona exist as euhedral crystals imbedded in micro granular, white colored anglesite with a saccharoidal texture. The associated minerals include phosgenite, wulfenite, leadhillite and caledonite. In Greece, the mammothite exists as small euhedral crystals and also as microscopic rock cavities lined with projecting crystals within the slags. The associated minerals here are cerussite, phosgenite and matlockite. The ideal chemical formula for mammothite is Pb6Cu4AlSb5+O2(OH)16Cl4(SO4)2.

<span class="mw-page-title-main">Penfieldite</span>

Penfieldite is a rare lead hydroxychloride mineral from the class of halides. It was named after Samuel Lewis Penfield. It has been a valid species before the founding of IMA, and was first published in 1892. It had been grandfathered, meaning the name penfieldite is still believed to refer to a valid species. When it was first described by Genth in 1892 from Laurion, Greece, the mineral had the formula of Pb3Cl4O.

Belloite is a Halide mineral first discovered in the Rio Tinto Mine in Sierra Gorda, Antofagasta, Chile in 1998. Belloite has the ideal chemical formula of Cu(OH)Cl. The mineral has been approved by the Commission on New Minerals and Mineral Names, IMA, to be named belloite, after Andrés de Jesús María y José Bello López, the founder of the Universidad de Chile. Samples of belloite are preserved in the collection of the Mineralogical Museum in Hamburg, Germany.

References

  1. ↑ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi: 10.1180/mgm.2021.43 . S2CID   235729616.
  2. ↑ Mineralienatlas
  3. 1 2 3 Handbook of Mineralogy
  4. 1 2 3 Mindat.org
  5. ↑ Phosgenite and Matlockite in Derbyshire (Part 1), T. Bridges, M.E. Smith, Journal of the Russell Society Volume 1, No. 2, p7-14, 1983 Retrieved on 2011-01-11
  6. ↑ Mawe, John. The Mineralogy of Derbyshire with a Description of the most Interesting Mines. 1802, London
  7. ↑ Frondell, Clifford. American Mineralogist, Vol 20, 469–473, 1935 Retrieved on 2011-01-11
  8. ↑ Nick Moyes (9 April 2011). Working with Wikipedia – a museum's perspective. Event occurs at 14:30. Retrieved 15 April 2011.
  9. ↑ "Matlockite Group". Mindat.org. Retrieved 12 January 2011.
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