Triploidite

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Triploidite
Triploidite-199681.jpg
Radial reddish triploidite from the Branchville Quarry, Branchville, Fairfield County, Connecticut, US (7.0 x 4.8 x 2.6 cm)
General
Category Phosphate minerals
Formula
(repeating unit)
(Mn,Fe)2PO4OH
IMA symbol Tpd [1]
Strunz classification 8.BB.15
Crystal system Monoclinic
Crystal class Prismatic (2/m)
(same H-M symbol)
Space group P21/a
Unit cell a = 12.36  Å, b = 13.27 Å
c = 9.94 Å; β = 108.23°; Z = 16
Identification
ColorRed-brown, light pink, yellow-brown; light pink to light brown in transmitted light.
Crystal habit Elongated and striated prismatic crystals; fibrous: columnar to spherulitic
Cleavage On {010}, good; on {120}, fair; on {110}, very poor.
Fracture Uneven to subconchoidal
Mohs scale hardness4+12 – 5
Luster Adamantine, vitreous, greasy
Streak White, off-white.
Diaphaneity Transparent, translucent
Specific gravity 3.70 measured
Optical propertiesBiaxial (+)
Refractive index nα = 1.725 nβ = 1.726 nγ = 1.730
Birefringence δ = 0.005
Pleochroism Weak
Dispersion r > v strong
Solubility Soluble in acids.
References [2] [3] [4]

Triploidite is an uncommon manganese iron phosphate mineral with formula: (Mn, Fe)2 PO4 OH . 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. [2]

It was first described in 1878 for an occurrence in the Branchville Quarry, Branchville, Fairfield County, Connecticut. The name is derived from its resemblance to triplite. [3]

It typically occurs as a hydrothermal alteration product of primary phosphate minerals in granite pegmatites. It occurs with triplite, lithiophilite, triphylite, eosphorite, dickinsonite and rhodochrosite. [2] [4]

It forms a solid solution series with the iron rich wolfeite. [3] [4]

See also

Related Research Articles

<span class="mw-page-title-main">Variscite</span> Hydrated aluminium phosphate

Variscite is a hydrated aluminium phosphate mineral (AlPO4·2H2O). It is a relatively rare phosphate mineral. It is sometimes confused with turquoise; however, variscite is usually greener in color. The green color results from the presence of small amounts of trivalent chromium (Cr3+
).

<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">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">Lazulite</span>

Lazulite ((Mg,Fe2+)Al2(PO4)2(OH)2) is a blue, phosphate mineral containing magnesium, iron, and aluminium phosphate. Lazulite forms one endmember of a solid solution series with the darker iron rich scorzalite.

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

Lithiophilite is a mineral containing the element lithium. It is lithium manganese(II) phosphate with chemical formula LiMnPO4. It occurs in pegmatites often associated with triphylite, the iron end member in a solid solution series. The mineral with intermediate composition is known as sicklerite and has the chemical formula Li(Mn,Fe)PO4). The name lithiophilite is derived from the Greek philos (φιλός) "friend", as lithiophilite is usually found with lithium.

<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">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">Eucryptite</span>

Eucryptite is a lithium bearing aluminium silicate mineral with formula LiAlSiO4. It crystallizes in the trigonal - rhombohedral crystal system. It typically occurs as granular to massive in form and may pseudomorphically replace spodumene. It has a brittle to conchoidal fracture and indistinct cleavage. It is transparent to translucent and varies from colorless to white to brown. It has a Mohs hardness of 6.5 and a specific gravity of 2.67. Optically it is uniaxial positive with refractive index values of nω = 1.570 - 1.573 and nε = 1.583 - 1.587.

<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">Eosphorite</span> Phosphate mineral

Eosphorite is a brown (occasionally pink) manganese hydrous phosphate mineral with chemical formula: MnAl(PO4)(OH)2·H2O. It is used as a gemstone.

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

Santabarbaraite is an amorphous ferric hydroxy phosphate mineral hydrate that was discovered in Tuscany, Italy during 2000. It also can be found in Victoria, Australia and Lake Baikal, Siberia.

<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">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">Hagendorfite</span>

Hagendorfite is an iron phosphate mineral with the chemical formula of (Na,Ca)MnFe2(PO4)3 and is named after where the mineral was discovered, Hagendorf-Süd, Bavaria, Germany.

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

Ludlamite is a rare phosphate mineral with chemical formula (Fe,Mn,Mg)3(PO4)2·4H2O. It was first described in 1877 for an occurrence in Wheal Jane mine in Cornwall, England and named for English mineralogist Henry Ludlam (1824–1880).

<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.

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.

Bobfergusonite is a mineral with formula Na2Mn5FeAl(PO4)6. The mineral varies in color from green-brown to red-brown. It was discovered in 1986 in Manitoba, Canada, and named for Robert Bury Ferguson (born 1920). As of 2012, the mineral has only been found in Canada and Argentina.

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

Serrabrancaite is a mineral with the chemical formula MnPO4•H2O and which is named for the locality where it was found, the Alto Serra Branca Pegmatite. The Alto Serra Branca mine has been in operation since the 1940s. It is located in Paraiba, Brazil near a village named Pedra Lavrada. Tantalite is the main mineral mined here. Specimens of serrabrancaite are kept in the Mineralogical Collections of both the Bergakademie Freiberg, Germany and the Martin-Luther Universität Halle, Institut für Geologische Wissenschaften.

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 Handbook of Mineralogy
  3. 1 2 3 Mindat
  4. 1 2 3 Webmineral data