Kidwellite

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Kidwellite
Kidwellite-160225.jpg
General
Category Mineral
Formula
(repeating unit)
NaFe3+9+x(PO4)6(OH)4·12H2O
(x ≈ 0.33)
IMA symbol Kdw
Strunz classification 08.DK.20
Dana classification42.08.02.01
Crystal system Monoclinic
Crystal class Prismatic
H-M Symbol: 2/m
Space group P2/c
Unit cell 1,393.77
Identification
Formula mass 1,368.34
ColorGreenish white, light green, greenish yellow, yellow
Cleavage Perfect on {100}
Fracture Splintery
Mohs scale hardness3
Luster Resinous, waxy, silky, dull
Streak Yellow
Diaphaneity Translucent
Specific gravity 3.04 – 3.3
Density Measured: 3.04 – 3.3
Calculated: 3.34
Optical propertiesBiaxial (−)
Refractive index nα = 1.787
nβ = 1.800
nγ = 1.805
Birefringence 0.018
Pleochroism None
Dispersion Extreme
Ultraviolet fluorescence None
Common impuritiesAluminum, Copper, Arsenic

Kidwellite in an uncommon mineral [1] that was discovered in Arkansas in the United States. It was approved by the IMA in 1974, [2] but it was only named in 1978 by Moore and Ito after Albert Lewis (Laws) Kidwell. [3]

Contents

Properties

Kidwellite usually has a botyroidal or acicular crystal habit. The luster of these spherical aggregates is usually matte and has a velvety surface. [3] However, it can grow fibrous columnar crystals, although that form is much rarer. Because of the similarities in hardness, color, and crystal habit, it can be confused with the sodium analogue of meurigite. An easy way to differentiate the two is that meurigite-Na has a white streak, [4] while kidwellite has a yellow one. [3] The mineral does not display radioactive properties. Kidwellite mainly consists of oxygen (44.43%) and iron (36.73%) but otherwise consists of phosphorus (13.58%). It also has a small amount of copper (2.32%), sodium (1.68%) and hydrogen (1.25%). [5] When originally described by Moore and Ito in 1978, the two researchers reported the mineral to crystallize in either A2/m, Am or A2 space group, which was later found out to be incorrect, as demonstrated by the structure solution. [6]

According to one sample, it can be slightly arsenic bearing as well. [3] The slightly arsenic samples were collected from the Clara Pit, Black Forest, Germany. This study was executed by the author of the journal, Uwe Kolitsch. He claimed the data to be similar to Walenta's results in 1990 executed on the samples from the same locality. [6] The specimens obtained from Clara Pit bearing arsenic can be explained easily, as many arsenic bearing minerals can be found in the mine. [7] Other impurities include aluminum and copper. [6] Comparing his findings with Moore's and Ito's, the author suggested revising both the chemical formula and the symmetry. It was accepted by the IMA, as both the formula and the space group is now the same as what Kolitsch described in his findings. [8]

Oriented intergrowths

Several authors reported kidwellite having epitaxial intergrowths with iron phosphates. In the Rotläufchen mine, Germany, Dietrich found kidwellite needles on the face of hydrothermally altered rockbridgeite in 1978. Keller reported a similar finding from Namibia in 1985, where he discovered older rockbridgeites with oriented overgrowths of fibrous kidwellite on it. In 1995, Walenta described dufrénite crystals that grade into kidwellite at their tip. The aforementioned mineralogist – among Theye – in 2001, observed the fibrous kidwellite grading into laubmannite. [6] The similarities between the structure of kidwellite and laubmannite, and other fibrous iron phosphates explains the reported epitaxial intergrowths. [9]

Discovery and locality

Kidwellite was described from novaculite deposits in Arkansas by Moore and Ito. Even though there are numerous occurrences of the mineral, kidwellite does not have mamy more studies on it other than the one made by the two aforementioned mineralogists. It is a late-stage or a secondary mineral. [6] It usually occurs in phosphate-bearing iron deposits, as a replacement of beraunite and rockbridgeite. [3] Kidwellite can be found in Arkansas, US, in the Coon Creek mine and the Three Oak Gap in Polk County. It can also be found in Alabama, Brazil, [5] Namibia, England, Germany, Australia, and a few more countries. [1] It can be associated with rockbridgeite, beraunite, strengite, cacoxenite, chalcosiderite, eleonorite, and dufrénite. [6]

Related Research Articles

<span class="mw-page-title-main">Torbernite</span> Copper uranyl phosphate mineral

Torbernite, also known as chalcolite, is a relatively common mineral with the chemical formula Cu[(UO2)(PO4)]2(H2O)12. It is a radioactive, hydrated green copper uranyl phosphate, found in granites and other uranium-bearing deposits as a secondary mineral. The chemical formula of torbernite is similar to that of autunite in which a Cu2+ cation replaces a Ca2+ cation. Torbernite tends to dehydrate to metatorbernite with the sum formula Cu[(UO2)(PO4)]2(H2O)8.

<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">Eudialyte</span> Cyclosilicate mineral

Eudialyte, whose name derives from the Greek phrase Εὖ διάλυτος, eu dialytos, meaning "well decomposable", is a somewhat rare, nine member ring cyclosilicate mineral, which forms in alkaline igneous rocks, such as nepheline syenites. Its name alludes to its ready solubility in acid.

<span class="mw-page-title-main">Olivenite</span> Copper arsenate mineral

Olivenite is a copper arsenate mineral, formula Cu2AsO4OH. It crystallizes in the monoclinic system (pseudo-orthorhombic), and is sometimes found in small brilliant crystals of simple prismatic habit terminated by domal faces. More commonly, it occurs as globular aggregates of acicular crystals, these fibrous forms often having a velvety luster; sometimes it is lamellar in structure, or soft and earthy.

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

Triplite is a rare phosphate mineral with formula: (Mn, Fe)2PO4(F, OH). It occurs in phosphate-rich granitic pegmatites typically as irregular brown opaque masses. Triplite was first described in 1813 for an occurrence in Chanteloube, Limousin, France. The name is from the Greek triplos for triple, in reference to the three cleavage directions. In color and appearance, it is very similar to rhodocrosite, another manganese bearing mineral. Chemically, it is also quite similar to triploidite the difference being that triplite is fluorine dominant while triploidite is hydroxide dominant.

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

Triphylite is a lithium iron(II) phosphate mineral with the chemical formula LiFePO4. It is a member of the triphylite group and forms a complete solid solution series with the lithium manganese(II) phosphate, lithiophilite. Triphylite crystallizes in the orthorhombic crystal system. It rarely forms prismatic crystals and is more frequently found in hypidiomorphic rock. It is bluish- to greenish-gray in color, but upon alteration becomes brown to black.

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

Austinite is a member of the adelite-descloizite group, adelite subgroup, the zinc (Zn) end member of the copper-Zn series with conichalcite. It is the zinc analogue of cobaltaustinite and nickelaustinite. At one time “brickerite” was thought to be a different species, but it is now considered to be identical to austinite. Austinite is named in honour of Austin Flint Rogers (1877–1957), American mineralogist from Stanford University, California, US.

<span class="mw-page-title-main">Todorokite</span> Hydrous manganese oxide mineral

Todorokite is a complex hydrous manganese oxide mineral with generic chemical formula (Na,Ca,K,Ba,Sr)
1-x
(Mn,Mg,Al)
6
O
12
·3-4H
2
O
. It was named in 1934 for the type locality, the Todoroki mine, Hokkaido, Japan. It belongs to the prismatic class 2/m of the monoclinic crystal system, but the angle β between the a and c axes is close to 90°, making it seem orthorhombic. It is a brown to black mineral which occurs in massive or tuberose forms. It is quite soft with a Mohs hardness of 1.5, and a specific gravity of 3.49 - 3.82. It is a component of deep ocean basin manganese nodules.

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

Triploidite is an uncommon manganese iron phosphate mineral with formula: (Mn, Fe)2PO4OH. It crystallizes in the monoclinic crystal system and typically occurs as elongated and striated slender prisms which may be columnar to fibrous. Its crystals may be pinkish to yellowish brown or red-orange.

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

Seamanite, named for discoverer Arthur E. Seaman, is a rare manganese boron phosphate mineral with formula Mn3[B(OH)4](PO4)(OH)2. The yellow to pink mineral occurs as small, needle-shaped crystals. It was first discovered in 1917 from a mine in Iron County, Michigan, United States and identified in 1930. As of 2012, seamanite is known from four sites in Michigan and South Australia.

<span class="mw-page-title-main">Djurleite</span> Copper sulfide mineral

Djurleite is a copper sulfide mineral of secondary origin with formula Cu31S16 that crystallizes with monoclinic-prismatic symmetry. It is typically massive in form, but does at times develop thin tabular to prismatic crystals. It occurs with other supergene minerals such as chalcocite, covellite and digenite in the enriched zone of copper orebodies. It is a member of the chalcocite group, and very similar to chalcocite, Cu2S, in its composition and properties, but the two minerals can be distinguished from each other by x-ray powder diffraction. Intergrowths and transformations between djurleite, digenite and chalcocite are common. Many of the reported associations of digenite and djurleite, however, identified by powder diffraction, could be anilite and djurleite, as anilite transforms to digenite during grinding.

Schreyerite (V2Ti3O9), is a vanadium, titanium oxide mineral found in the Lasamba Hill, Kwale district in Coast Province, Kenya. It is polymorphous with kyzylkumite.

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

Beraunite is an iron phosphate mineral. It was first described by August Breithaupt for an occurrence in Beraun currently in the Czech Republic. Beraunite occurs as a secondary mineral in iron ore deposits, and as an alteration product of primary phosphate minerals in granite pegmatites.

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

Cyrilovite (NaFe33+(PO4)2(OH)4·2(H2O)) is a hydrous sodium iron phosphate mineral. It is isomorphous and isostructural with wardite, the sodium aluminium counterpart.

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

Hureaulite is a manganese phosphate with the formula Mn2+5(PO3OH)2(PO4)2·4H2O. It was discovered in 1825 and named in 1826 for the type locality, Les Hureaux, Saint-Sylvestre, Haute-Vienne, Limousin, France. It is sometimes written as huréaulite, but the IMA does not recommend this for English language text.

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

Minyulite is a rare phosphate mineral with a chemical formula of KAl2(PO4)2F·4(H2O).

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

Allanpringite is a phosphate mineral named after Australian mineralogist Allan Pring of the South Australian Museum. Allanpringite is a Fe3+ analogue Al-phosphate mineral wavellite, but it has a different crystal symmetry – monoclinic instead of orthorhombic in wavellite. It forms needle-like crystals, which are always twinned and form parallel bundles up to about 2 mm long. They are often found in association with other iron phosphates in abandoned iron mines.

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

Satterlyite is a hydroxyl bearing iron phosphate mineral. The mineral can be found in phosphatic shales and was first discovered in the Big Fish River area in Yukon Territory, Canada.

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.

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.

References

  1. 1 2 Minerals, Dakota Matrix. "Kidwellite mineral information and data". www.dakotamatrix.com. Retrieved 2022-10-20.
  2. "The New IMA List of Minerals – A Work in Progress" (PDF). September 2019.{{cite journal}}: Cite journal requires |journal= (help)
  3. 1 2 3 4 5 "Kidwellite". www.mindat.org. Retrieved 2022-10-20.
  4. "Meurigite-Na". www.mindat.org. Retrieved 2022-10-20.
  5. 1 2 "Kidwellite Mineral Data". www.webmineral.com. Retrieved 2022-10-20.
  6. 1 2 3 4 5 6 Kolitsch, Uwe (2004). "The crystal structures of kidwellite and 'laubmannite', two complex fibrous iron phosphates" (PDF). Mineralogical Magazine. 68 (1): 147–165. doi:10.1180/0026461046810177. S2CID   53137259.
  7. "Clara Pit", Wikipedia, 2022-08-10, retrieved 2022-10-20
  8. "Publications Detail View". fgga.univie.ac.at. Retrieved 2022-10-20.
  9. Kolitsch, U. (February 2004). "The crystal structures of kidwellite and 'laubmannite', two complex fibrous iron phosphates". Mineralogical Magazine. 68 (1): 147–165. doi:10.1180/0026461046810177. ISSN   0026-461X. S2CID   53137259.