Tarbuttite

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Tarbuttite
Tarbuttite.JPG
Tarbuttite from Broken Hill mine (Kabwe mine) in Central Province, Zambia
General
Category Phosphate minerals
Formula
(repeating unit)		Zn2(PO4)(OH)
IMA symbol Tbt [1]
Strunz classification 8.BB.35
Dana classification41.6.7.1
Crystal system Triclinic
Crystal class Pinacoidal (1)
(same H-M symbol)
Space group P1
Unit cell a = 5.400  Å, b = 5.654 Å
c = 6.465 Å, α = 102.51°
β = 102.46°, γ = 86.50°
Z = 2 [2]
Identification
ColorWhite, colorless, yellow, red, green, or brown
Crystal habit Equant to short prismatic [001], sheaf-like aggregates, crusts, individual crystals rounded and deeply striated
Cleavage Perfect on {010}
Fracture Irregular, uneven
Mohs scale hardness3.5
Luster Vitreous, pearly on cleavages [2]
Streak White
Diaphaneity Transparent, translucent
Specific gravity 4.12; 4.19 (calc.)
Density 4.12 g/cm3 (measured)
Optical propertiesBiaxial (−)
Refractive index nα = 1.660
nβ = 1.705
nγ = 1.713
Birefringence δ = 0.053
2V angle 50° (measured)
Dispersion Weak, [3] strong [2]
Ultraviolet fluorescence Non-fluorescent [4]
References [3]

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.

Contents

Description and habit

Tarbuttite is white, yellow, red, green, brown, or colorless; in transmitted light it is colorless. [3] Traces of copper cause green coloring, while iron hydroxides cause the other colors. Colorless crystals tend to be transparent while colored specimens have varying degrees of transparency. [5]

The mineral occurs as equant to short prismatic crystals up to 2 cm (0.79 in), in sheaf-like or saddle-shaped aggregates, or as crusts. [2] Individual crystals are commonly rounded and striated. [3]

Structure

Zinc ions are surrounded by oxygen in a nearly perfect trigonal bipyramid and phosphate groups are tetrahedral. The crystal structure consists of zig-zag chains of Zn1 polyhedra linked by phosphate groups and pairs of Zn2 polyhedra. In each unit cell are two formula units of Zn2(PO4)(OH). [6]

History

Tarbuttite was discovered in 1907 in Broken Hill mine, Northern Rhodesia, (now Kabwe, Zambia). [3] [7] The mineral was described from specimens in cellular limonite in the largest hill of the group, Kopje No. 2. [8] [9] In a cave discovered in Kopje No. 1 by boring a tunnel, [7] tarbuttite was also found in association with hopeite as obscure crystals and crystals smaller than 1⁄16 mm (0.0025 in) [9] and as an encrustation on some bones. [10] Several specimens of the mineral were collected by Percy Coventry Tarbutt, a director of the Broken Hill Exploration Company. [5] [8] In 1907, the name tarbuttite was proposed by L.J. Spencer in the journal Nature in honor of Tarbutt. [5]

When the International Mineralogical Association was founded, tarbuttite was grandfathered as a valid mineral species. [3]

Occurrence

Tarbuttite has been found in Algeria, Angola, Australia, Canada, China, Namibia, the United States, and Zambia. [2] [3]

Tarbuttite forms as secondary mineral in oxidized zinc deposits. It has been found in association with cerussite, descloizite, hemimorphite, hopeite, hydrozincite, "limonite", parahopeite, pyromorphite, scholzite, smithsonite, and vanadinite. [2]

See also

Related Research Articles

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

Vivianite (Fe2+
3(PO
4)
2·8H
2O) is a hydrated iron phosphate mineral found in a number of geological environments. Small amounts of manganese Mn2+, magnesium Mg2+, and calcium Ca2+ may substitute for iron Fe2+ in the structure. Pure vivianite is colorless, but the mineral oxidizes very easily, changing the color, and it is usually found as deep blue to deep bluish green prismatic to flattened crystals.
Vivianite crystals are often found inside fossil shells, such as those of bivalves and gastropods, or attached to fossil bone.

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

Wardite is a hydrous sodium aluminium phosphate hydroxide mineral with formula: NaAl3(PO4)2(OH)4·2(H2O). Wardite is of interest for its rare crystallography. It crystallizes in the tetragonal trapezohedral class and is one of only a few minerals in that class. Wardite forms vitreous green to bluish green to white to colorless crystals, masses, and fibrous encrustations. It has a Mohs hardness of 5 and a specific gravity of 2.81–2.87.

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

Brazilianite, whose name derives from its country of origin, Brazil, is a typically yellow-green phosphate mineral, most commonly found in phosphate-rich pegmatites.

<span class="mw-page-title-main">Adamite</span> Zinc arsenate hydroxide mineral

Adamite is a zinc arsenate hydroxide mineral, Zn2AsO4OH. It is a mineral that typically occurs in the oxidized or weathered zone above zinc ore occurrences. Pure adamite is colorless, but usually it possess yellow color due to Fe compounds admixture. Tints of green also occur and are connected with copper substitutions in the mineral structure. Olivenite is a copper arsenate that is isostructural with adamite and there is considerable substitution between zinc and copper resulting in an intermediate called cuproadamite. Zincolivenite is a recently discovered mineral being an intermediate mineral with formula CuZn(AsO4)(OH). Manganese, cobalt, and nickel also substitute in the structure. An analogous zinc phosphate, tarbuttite, is known.

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

Hopeite is a hydrated zinc phosphate with formula: Zn3(PO4)2·4H2O. It is a rare mineral used mainly as a collectors specimen.

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

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

Fluorapatite, often with the alternate spelling of fluoroapatite, is a phosphate mineral with the formula Ca5(PO4)3F (calcium fluorophosphate). Fluorapatite is a hard crystalline solid. Although samples can have various color (green, brown, blue, yellow, violet, or colorless), the pure mineral is colorless, as expected for a material lacking transition metals. Along with hydroxylapatite, it can be a component of tooth enamel, but for industrial use both minerals are mined in the form of phosphate rock, whose usual mineral composition is primarily fluorapatite but often with significant amounts of the other.

<span class="mw-page-title-main">Augelite</span> Aluminium phosphate mineral

Augelite is an aluminium phosphate mineral with formula: Al2(PO4)(OH)3. The shade varies from colorless to white, yellow or rose. Its crystal system is monoclinic.

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

Arthurite is a mineral composed of divalent copper and iron ions in combination with trivalent arsenate, phosphate and sulfate ions with hydrogen and oxygen. Initially discovered by Sir Arthur Russell in 1954 at Hingston Down Consols mine in Calstock, Cornwall, England, arthurite is formed as a resultant mineral in the oxidation region of some copper deposits by the variation of enargite or arsenopyrite. The chemical formula of Arthurite is CuFe23+(AsO4,PO4,SO4)2(O,OH)2·4H2O.

<span class="mw-page-title-main">Coconinoite</span> Uranium ore

Coconinoite is a uranium ore that was discovered in Coconino County, Arizona. It is a phosphate mineral; or uranyl phosphate mineral along with other subclass uranium U6+ minerals like blatonite, boltwoodite, metazeunerite and rutherfordine.

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

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<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.

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

Zinclipscombite is a dark-green to brown zinc iron phosphate mineral with the formula Zn(Fe3+)2(PO4)2(OH)2. It occurs as fibrous spheres and exhibits tetragonal crystal structure.

Gatehouseite is a manganese hydroxy phosphate mineral with formula Mn5(PO4)2(OH)4. First discovered in 1987, it was identified as a new mineral species in 1992 and named for Bryan M. K. C. Gatehouse (born 1932). As of 2012, it is known from only one mine in South Australia.

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

Collinsite is a mineral with chemical formula Ca
2(Mg,Fe2+
)(PO
4)
2•2H
2O. It was discovered in British Columbia, Canada, and formally described in 1927. It was named in honor of William Henry Collins (1878–1937), director of the Geological Survey of Canada. There are three varieties of the mineral: magnesian collinsite, zincian collinsite, and strontian collinsite. The crystal structure consists of polyhedral chains linked by weak hydrogen bonds.

Falsterite is a rare phosphate mineral with the formula Ca2MgMn2+2(Fe2+0.5Fe3+0.5)4Zn4(PO4)8(OH)4(H2O)14. It is a pegmatitic mineral, related to the currently approved mineral ferraioloite.

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

Zigrasite is a phosphate mineral with the chemical formula of MgZr(PO4)2(H2O)4. Zigrasite was discovered and is only known to occur in the Dunton Quarry at Oxford County, Maine. Zigrasite was specifically found in the giant 1972 gem tourmaline-bearing pocket at the Dunton Quarry. Zigrasite is named after James Zigras who originally discovered and brought the mineral to attention.

Zincoberaunite is an iron and zinc phosphate mineral, the Zn analogue of beraunite. It was first described by Chukanov et al. for an occurrence in Hagendorf Sud pegmatite in Germany. Zincoberaunite occurs as a secondary mineral as an alteration product of primary phosphate minerals in granite pegmatites.

Rockbridgeite is an anhydrous phosphate mineral in the "Rockbridgeite" supergroup with the chemical formula Fe2+Fe3+4(PO4)3(OH)5. It was discovered at the since-shut-down Midvale Mine in Rockbridge County, Virginia, United States. The researcher who first identified it, Clifford Frondel, named it in 1949 for its region of discovery, Rockbridge County.

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 "Tarbuttite" (PDF). Handbook of Mineralogy. Mineral Data Publishing. Retrieved July 13, 2012.
  3. 1 2 3 4 5 6 7 "Tarbuttite". Mindat. Retrieved July 13, 2012.
  4. ↑ "Tarbuttite". Webmineral. Retrieved July 13, 2012.
  5. 1 2 3 Spencer, p. 22.
  6. ↑ Cocco, p. 321.
  7. 1 2 Spencer, p. 1.
  8. 1 2 Spencer, p. 2.
  9. 1 2 Spencer, p. 30.
  10. ↑ Spencer, p. 31.

Bibliography

Further reading

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