Tsumcorite

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Tsumcorite
Tsumcorite-160209.jpg
Tsumcorite from the Tsumeb Mine, Namibia
General
Category Arsenate minerals
Formula
(repeating unit)
PbZnFe2+(AsO4)2.H2O
IMA symbol Tmc [1]
Strunz classification 8.CG.15
Dana classification 40.02.09.01
Crystal system Monoclinic
Crystal class Prismatic (2/m)
(same H-M symbol)
Space group C2/m (no. 12)
Unit cell a = 9.124  Å, b = 6.329 Å
c = 7.577 Å; β = 115.3°; Z = 2
Identification
Formula mass 624.29 g/mol
ColorYellow-brown, red-brown, orange
Crystal habit Radiating, fibrous crusts
Twinning Common, on an unknown law
Cleavage Good on {001}
Mohs scale hardness4+12
Luster Vitreous
Streak Yellow
Diaphaneity Translucent
Specific gravity 5.2
Optical propertiesBiaxial
Refractive index nα = 1.87–1.91 nβ = 1.89–1.93 nγ = 1.92–1.96
Pleochroism Weak, yellow to yellow-green
2V angle 67–83.5°
Solubility Dissolves in HCl
References [2] [3] [4] [5] [6] [7]

Tsumcorite is a rare hydrated lead arsenate mineral that was discovered in 1971, and reported by Geier, Kautz and Muller. [6] It was named after the TSUMeb CORporation mine at Tsumeb, in Namibia, in recognition of the Corporation's support for mineralogical investigations of the orebody at its Mineral Research Laboratory. [5]

Contents

Unit cell

Tsumcorite belongs to the monoclinic crystal class 2/m, which means that it has a twofold axis of symmetry along the b axis and a mirror plane perpendicular to this, in the plane containing the a and c axes. The a and c axes are inclined to each other at angle β = 115.3°. The unit cell parameters are a = 9.124 Å to 9.131 Å, b = 6.326 Å to 6.329 Å and c = 7.577 Å to 7.583 Å. [2] [3] [4] [6] There are two formula units per unit cell (Z = 2), and the space group is C2/m, meaning that the cell is a C-face centred lattice, with lattice points in the center of the C face as well as at the corners of the cell. [8] The structure is related to the brackebushite group structure. [2]

Mineral series

Tsumcorite belongs to the helmutwinklerite group, [2] whose members are

Tsumcorite forms a series with helmutwinklerite as Zn replaces the Fe2+, with thometzekite as Cu replaces the Zn and Fe2+, [2] [4] and also with mawbyite. [9]

Crystal habit and properties

Crystals are prismatic, elongated along the b axis, or wedge-shaped. They occur in radiating sheaves and spherulites, and as fibrous crusts or earthy and powdery material. [5] Cleavage is good perpendicular to the c axis, [5] and twinning is common. [5]

Tsumcorite is yellow-brown, red-brown or orange in color, and it is one of the few minerals that have a yellow streak (orpiment and crocoite are two others). It is translucent, with a vitreous luster, and dichroic yellow to yellow-green. [2] [6] The optical class is biaxial and the refractive indices are approximately equal to 1.90. [2] [4] [6]

The mineral is moderately hard, with a Mohs hardness of 4+12, between fluorite and apatite, [2] [3] [4] [5] and quite heavy, due to the lead content, with specific gravity 5.2, which is more than baryte but less than cerussite. It dissolves in hydrochloric acid [2] [6] and it is not radioactive. [4]

Occurrence and associations

Tsumcorite is a rare secondary mineral in the oxidized zone of some arsenic-bearing hydrothermal lead-zinc deposits. [2] [5] [6]

The type locality is the Tsumeb Mine, Tsumeb, Otjikoto Region, Namibia, where it is associated with willemite, smithsonite, mimetite, scorodite, anglesite, arseniosiderite, beaverite, beudantite, carminite, ludlockite, o'danielite, zincroselite, stranskiite and leiteite. [5] At the Puttapa Mine in Australia it occurs with adamite, mimetite, smithsonite, goethite and quartz. [5] At the Kintore Open Cut, Broken Hill, Australia it occurs with segnitite, beudantite, carminite and mawbyite. [9]

Related Research Articles

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Wulfenite is a lead molybdate mineral with the formula PbMoO4. It often occurs as thin tabular crystals with a bright orange-red to yellow-orange color, sometimes brown, although the color can be highly variable. In its yellow form it is sometimes called "yellow lead ore".

<span class="mw-page-title-main">Mimetite</span> Lead arsenate chloride mineral

Mimetite is a lead arsenate chloride mineral (Pb5(AsO4)3Cl) which forms as a secondary mineral in lead deposits, usually by the oxidation of galena and arsenopyrite. The name derives from the Greek Μιμητής mimetes, meaning "imitator" and refers to mimetite's resemblance to the mineral pyromorphite. This resemblance is not coincidental, as mimetite forms a mineral series with pyromorphite (Pb5(PO4)3Cl) and with vanadinite (Pb5(VO4)3Cl). Notable occurrences are Mapimi, Durango, Mexico and Tsumeb, Namibia.

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

Vauxite is a phosphate mineral with the chemical formula Fe2+Al2(PO4)2(OH)2·6(H2O). It belongs to the laueite – paravauxite group, paravauxite subgroup, although Mindat puts it as a member of the vantasselite Al4(PO4)3(OH)3·9H2O group. There is no similarity in structure between vauxite and paravauxite Fe2+Al2(PO4)2(OH)2·8H2O or metavauxite Fe3+Al2(PO4)2(OH)2·8H2O, even though they are closely similar chemically and all minerals occur together as secondary minerals. Vauxite was named in 1922 for George Vaux Junior (1863–1927), an American attorney and mineral collector.

<span class="mw-page-title-main">Hexagonal crystal family</span> Union of crystal groups with related structures and lattices

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<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">Conichalcite</span> Arsenate mineral

Conichalcite, CaCu(AsO4)(OH), is a relatively common arsenate mineral related to duftite (PbCu(AsO4)(OH)). It is green, often botryoidal, and occurs in the oxidation zone of some metal deposits. It occurs with limonite, malachite, beudantite, adamite, cuproadamite, olivenite and smithsonite.

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

Plumbogummite is a rare secondary lead phosphate mineral, belonging to the alunite supergroup of minerals, crandallite subgroup. Some other members of this subgroup are:

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

Lavendulan is an uncommon copper arsenate mineral, known for its characteristic intense electric blue colour. It belongs to the lavendulan group, which has four members:

<span class="mw-page-title-main">Beudantite</span> Secondary mineral of the alunite group

Beudandite is a secondary mineral occurring in the oxidized zones of polymetallic deposits. It is a lead, iron, arsenate, sulfate with endmember formula: PbFe3(OH)6SO4AsO4.

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

Tsumebite is a rare phosphate mineral named in 1912 after the locality where it was first found, the Tsumeb mine in Namibia, well known to mineral collectors for the wide range of minerals found there. Tsumebite is a compound phosphate and sulfate of lead and copper, with hydroxyl, formula Pb2Cu(PO4)(SO4)(OH). There is a similar mineral called arsentsumebite, where the phosphate group PO4 is replaced by the arsenate group AsO4, giving the formula Pb2Cu(AsO4)(SO4)(OH). Both minerals are members of the brackebuschite group.

This list gives an overview of the classification of non-silicate minerals and includes mostly International Mineralogical Association (IMA) recognized minerals and its groupings. This list complements the List of minerals recognized by the International Mineralogical Association series of articles and List of minerals. Rocks, ores, mineral mixtures, not IMA approved minerals, not named minerals are mostly excluded. Mostly major groups only, or groupings used by New Dana Classification and Mindat.

<span class="mw-page-title-main">Warikahnite</span> Rare zinc arsenate mineral

Warikahnite is a rare zinc arsenate mineral of the triclinic crystal system with Hermann-Mauguin notation 1, belonging to the space group P1. It occurs in the Tsumeb mine in Namibia on corroded tennantite in the second oxidation zone under hydrothermal conditions in a dolomite-hosted polymetallic ore deposit. It is associated with adamite, stranskiite, koritnigite, claudetite, tsumcorite, and ludlockite. The origin of discovery was in a dolomite ore formation within an oxidized hydrothermal zone, in the E9 pillar, 31st level of the Tsumeb Mine in Namibia, Southwest Africa. It has also been found at Lavrion, Greece and Plaka, Greece as microscopic white needles.

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

Ianbruceite is a rare hydrated zinc arsenate with the formula [Zn2(OH)(H2O)(AsO4)](H2O)2; material from the Driggith mine has traces of cobalt. It was first discovered at Tsumeb, approved by the International Mineralogical Association as a new mineral species in 2011, reference IMA2011-49, and named for Ian Bruce, who founded "Crystal Classics" in the early 1990s, and was heavily involved in attempts to reopen the famous Tsumeb mine for specimen mining.
In 2013 new occurrences of ianbruceite were reported from the neighbouring Driggith and Potts Gill mines on High Pike in the Caldbeck Fells, Cumbria, England. Here the mineral is probably a post-mining product. Caldbeck Fells and Tsumeb are the only reported localities for ianbruceite to date (May 2013).

<span class="mw-page-title-main">Hidalgoite</span> Mineral of the beudantite group

Hidalgoite, PbAl3(AsO4)(SO4)(OH)4, is a rare member of the beudantite group and is usually classified as part of the alunite family. It was named after the place where it was first discovered, the Zimapán mining district, Hidalgo, Mexico. At Hidalgo where it was initially discovered, it was found as dense white masses in alternating dikes of quartz latite and quartz monzonite alongside other secondary minerals such as sphalerite, arsenopyrite, cerussite and trace amounts of angelsite and alamosite, it was then rediscovered at other locations such as Australia where it occurs on oxidized shear zones above greywacke shales especially on the anticline prospects of the area, and on fine grained quartz-spessartine rocks in Broken Hill, Australia. Hidalgoite specimens are usually associated with copper minerals, clay minerals, iron oxides and polymetallic sulfides in occurrence.

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

Köttigite is a rare hydrated zinc arsenate which was discovered in 1849 and named by James Dwight Dana in 1850 in honour of Otto Friedrich Köttig (1824–1892), a German chemist from Schneeberg, Saxony, who made the first chemical analysis of the mineral. It has the formula Zn3(AsO4)2·8H2O and it is a dimorph of metaköttigite, which means that the two minerals have the same formula, but a different structure: köttigite is monoclinic and metaköttigite is triclinic. There are several minerals with similar formulae but with other cations in place of the zinc. Iron forms parasymplesite Fe2+3(AsO4)2·8H2O; cobalt forms the distinctively coloured pinkish purple mineral erythrite Co3(AsO4)2·8H2O and nickel forms annabergite Ni3(AsO4)2·8H2O. Köttigite forms series with all three of these minerals and they are all members of the vivianite group.

<span class="mw-page-title-main">Carminite</span> Anhydrous arsenate mineral containing hydroxyl

Carminite (PbFe3+2(AsO4)2(OH)2) is an anhydrous arsenate mineral containing hydroxyl. It is a rare secondary mineral that is structurally related to palermoite (Li2SrAl4(PO4)4(OH)4). Sewardite (CaFe3+2(AsO4)2(OH)2) is an analogue of carminite, with calcium in sewardite in place of the lead in carminite. Mawbyite is a dimorph (same formula, different structure) of carminite; mawbyite is monoclinic and carminite is orthorhombic. It has a molar mass of 639.87 g. It was discovered in 1850 and named for the characteristic carmine colour.

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

Mottramite is an orthorhombic anhydrous vanadate hydroxide mineral, PbCu(VO4)(OH), at the copper end of the descloizite subgroup. It was formerly called cuprodescloizite or psittacinite (this mineral characterized in 1868 by Frederick Augustus Genth). Duhamelite is a calcium- and bismuth-bearing variety of mottramite, typically with acicular habit.

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

Talmessite is a hydrated calcium magnesium arsenate, often with significant amounts of cobalt or nickel. It was named in 1960 for the type locality, the Talmessi mine, Anarak district, Iran. It forms a series with β-Roselite, where cobalt replaces some of the magnesium, and with gaitite, where zinc replaces the magnesium. All these minerals are members of the fairfieldite group. Talmessite is dimorphic with wendwilsonite.

<span class="mw-page-title-main">Segnitite</span> Common iron oxide mineral

Segnitite is a lead iron(III) arsenate mineral. Segnitite was first found in the Broken Hill ore deposit in Broken Hill, New South Wales, Australia. In 1991, segnitite was approved as a new mineral. Segnitite has since been found worldwide near similar locality types where rocks are rich in zinc and lead especially. it was named for Australian mineralogist, gemologist and petrologist Edgar Ralph Segnit. The mineral was named after E. R. Segnit due to his contributions to Australian mineralogy.

Gallobeudantite is a secondary, Gallium-bearing mineral of beudantite, where the Iron is replaced with Gallium, a rare-earth metal. It was first described as a distinct mineral by Jambor et al in 1996. Specific Gallium minerals are generally rare and Gallium itself is usually obtained as a by-product during the processing of the ores of other metals. In particular, the main source material for Gallium is bauxite, a key ore of aluminium. However, Gallobeudantite is too rare to be of economic value. Its main interest is academic and also among mineral collectors.

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. 1 2 3 4 5 6 7 8 9 10 Gaines et al (1997) Dana’s New Mineralogy Eighth Edition. Wiley
  3. 1 2 3 Mindat.org
  4. 1 2 3 4 5 6 Webmineral data
  5. 1 2 3 4 5 6 7 8 9 Handbook of Mineralogy
  6. 1 2 3 4 5 6 7 Fleischer M (1972) New mineral names, American Mineralogist 57, 1558, being a summary of Geier, Kautz and Muller (1971) Neues Jahrbuch für Mineralogie (Monatshefte) 1971: 304–309
  7. Tillmanns, E.; Gebert, W. (1 December 1973). "The crystal structure of tsumcorite, a new mineral from the Tsumeb mine, S. W. Africa". Acta Crystallographica Section B: Structural Crystallography and Crystal Chemistry. 29 (12): 2789–2794. doi:10.1107/S0567740873007545.
  8. Crystallography (1993) Walter Borchardt-Ott, Springer Verlag
  9. 1 2 Australian Journal of Mineralogy (1997) 3-1:62