On graftonite, a new mineral from Grafton, New Hampshire, and its intergrowth with triphylite

Penfield, S. L.

doi:10.2475/ajs.s4-9.49.20

Cited by 8 publications

(7 citation statements)

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“…The Mn-poor landesite-like phosphate, with a dark brown to black color, analyzed by Penfield (1900) and by John (1900), and discussed by Mason (1941), likely corresponds here to the mineral identified as kryzhanovskite.…”

Section: Discussionmentioning

confidence: 92%

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Complex Mechanisms of Alteration in a Graftonite + Sarcopside + Triphylite Association From the Luna Pegmatite, Piona, Lecco Province, Italy

Vignola¹,

Diella²,

Ferrari³

et al. 2011

The Canadian Mineralogist

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Phosphate masses have been found in a pegmatite rich in oligoclase, with minor muscovite and schorl, outcropping at Luna, near Piona, Lecco Province, Italy. These masses consist of sarcopside lamellae embedded in graftonite with minor triphylite with a well-developed alteration rim. Chemical analyses made with an electron microprobe and the X-ray powder-diffraction method allowed us to identify the following alteration-induced phosphate minerals: ferrisicklerite, heterosite, kryzhanovskite, ferrostrunzite, jahnsite-(CaMnFe), rockbridgeite, lipscombite, and whitmoreite. Petrographic observations of the textures allowed us to decipher the complex mechanism of alteration. The first sequence of alteration, due to hydrothermal topotactic transformation of triphylite into ferrisicklerite and heterosite, is marked by a progressive leaching of Li and by concomitant oxidation of Fe and Mn. The second one involves graftonite, sarcopside and the alteration products of triphylite. It is characterized by a progressive leaching of Ca in oxidizing and hydration conditions. The first step of the second sequence shows an almost complete preservation of the lamellar texture of the primary assemblage graftonite + sarcopside, and produces kryzhanovskite and ferrostrunzite. Kryzhanovskite displays two different chemical compositions, reflecting those of the primary graftonite and sarcopside: the Fe:Mn ratio is preserved. The second step shows the formation of the paragenesis jahnsite-(CaMnFe) + rockbridgeite + lipscombite. In a later episode of alteration, whitmoreite occurs as the result of the auto-oxidation process of ferrostrunzite. This process suggests that a phosphoferrite-like mineral previously occurred in the first step and then transformed into kryzanovskite by auto-oxidation as well.

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Section: Discussionmentioning

confidence: 92%

“…He used the analytical data of Penfield (1900) for samples from Grafton, New Hampshire, and those of John (1900) for samples from Cyrillhof, Moravia. In his developed inner lamellar texture.…”

Section: Introductionmentioning

confidence: 99%

Complex Mechanisms of Alteration in a Graftonite + Sarcopside + Triphylite Association From the Luna Pegmatite, Piona, Lecco Province, Italy

Vignola¹,

Diella²,

Ferrari³

et al. 2011

The Canadian Mineralogist

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“…The structure of graftonite-beusite is a dense framework of polyhedra, with extensive edge-and corner-sharing (Hawthorne, 1998;Huminicki and Hawthorne, 2002) between phosphate tetrahedra and [5]-to [8]-coordinated divalent-metal-oxide polyhedra. There has been extensive discussion as to the coordination numbers of the M(1), M(2) and M(3) sites in the graftonite-beusite structure; detailed examination of the issue by Tait et al (2013)…”

Section: Structural Considerationsmentioning

confidence: 99%

“…Graftonite , ideally (PO 4 ) 2 , was described from a granitic pegmatite in New Hampshire by Penfield (1900). Beus (1950) and Brooks and Shipway (1960) reported a graftonite-like mineral with Mn 2+ dominant over Fe 2+ , and beusite, ideally (PO 4 ) 2 , was formally described as a distinct species from the pegmatites of the San Luis area, Argentina, by Hurlbut and Aristarain (1968).…”

Section: Introductionmentioning

confidence: 99%

Classification of the minerals of the graftonite group

Hawthorne

Pieczka

2018

Mineral. mag.

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2 Abstract A classification and nomenclature scheme has been approved by the IMA-CNMNC (memorandum 66-SM/17) for the minerals of the graftonite group. The crystal structures of these minerals have three distinct sites that are occupied by Fe 2+ , Mn 2+ and Ca 2+ . These sites have coordination numbers [8], [5] and [6], and these differences lead to very strong order of Fe 2+ , Mn 2+ and Ca 2+ over these sites. As a result of this strong order, the following compositions have been identified as distinct species: graftonite: FeFe 2 (PO 4 ) 2 ; graftonite-(Ca): CaFe 2 (PO 4 ) 2 ;graftonite-(Mn): MnFe 2 (PO 4 ) 2 ; beusite: MnMn 2 (PO 4 ) 2 ; beusite-(Ca): CaMn 2 (PO 4 ) 2 .

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“…They have also been found as constituents of phosphate-oxide inclusions in IIIAB iron meteorites (Bild, 1974; Steele et al ., 1991; Olsen et al , 1999), and Stalder and Rozendaal (2002) reported graftonite as a primary phase in a phosphorous-rich iron formation. Penfield (1900) described graftonite, ideally [(PO 4 ) 2 ], from a granitic pegmatite in New Hampshire. Beus (1950) reported a graftonite-like mineral with Mn 2+ dominant over Fe 2+ , and Hurlbut and Aristarain (1968) described beusite, ideally [(PO 4 ) 2 ], as a distinct species from the pegmatites of the San Luis province, Argentina.…”

Section: Introductionmentioning

confidence: 99%

Beusite-(Ca), ideally CaMn₂²⁺(PO₄)₂, a new graftonite-group mineral from the Yellowknife pegmatite field, Northwest Territories, Canada: Description and crystal structure

et al. 2018

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Beusite-(Ca), ideally Ca${\rm Mn}_{\rm 2}^{2 +} $(PO4)2, is a new graftonite-group mineral from the Yellowknife pegmatite field, Northwest Territories, Canada. It occurs in a beryl–columbite–phosphate rare-element pegmatite where it is commonly intergrown with triphylite–lithiophilite or sarcopside, and may form by exsolution from a high-temperature (Li,Ca)-rich graftonite-like parent phase. It occurs as pale-brown lamellae 0.1–1.5 mm wide in triphylite, and is pale brown with a vitreous lustre and a very pale-brown streak. It is brittle, has a Mohs hardness of 5, and the calculated density is 3.610 g/cm3. Beusite-(Ca) is colourless in plane-polarized light, and is biaxial (+) with α = 1.685(2), β = 1.688(2), γ = 1.700(5), and the optic axial angle is 46.0(5)°. It is non-pleochroic with X || b; Y ˄ a = 40.3° in β obtuse; Z ˄ a = 49.7° in β acute. Beusite-(Ca) is monoclinic, has space group P21/c, a = 8.799(2), b = 11.724(2), c = 6.170(1) Å, β = 99.23(3)°, V = 628.3(1) Å3 and Z = 4. Chemical analysis by electron microprobe gave P2O5 41.63, FeO 19.43, MnO 23.63, CaO 15.45, sum 100.14 wt.%. The empirical formula was normalized on the basis of 8 anions pfu: (Ca0.94Fe0.92Mn1.13)Σ2.99(PO4)2.00. The crystal structure was refined to an R1 index of 1.55%. Beusite-(Ca) is a member of the graftonite group with Ca completely ordered at the [8]-coordinated M(1) site.

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On graftonite, a new mineral from Grafton, New Hampshire, and its intergrowth with triphylite

Cited by 8 publications

References 0 publications

Complex Mechanisms of Alteration in a Graftonite + Sarcopside + Triphylite Association From the Luna Pegmatite, Piona, Lecco Province, Italy

Complex Mechanisms of Alteration in a Graftonite + Sarcopside + Triphylite Association From the Luna Pegmatite, Piona, Lecco Province, Italy

Classification of the minerals of the graftonite group

Beusite-(Ca), ideally CaMn₂²⁺(PO₄)₂, a new graftonite-group mineral from the Yellowknife pegmatite field, Northwest Territories, Canada: Description and crystal structure

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On graftonite, a new mineral from Grafton, New Hampshire, and its intergrowth with triphylite

Cited by 8 publications

References 0 publications

Complex Mechanisms of Alteration in a Graftonite + Sarcopside + Triphylite Association From the Luna Pegmatite, Piona, Lecco Province, Italy

Complex Mechanisms of Alteration in a Graftonite + Sarcopside + Triphylite Association From the Luna Pegmatite, Piona, Lecco Province, Italy

Classification of the minerals of the graftonite group

Beusite-(Ca), ideally CaMn22+(PO4)2, a new graftonite-group mineral from the Yellowknife pegmatite field, Northwest Territories, Canada: Description and crystal structure

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Beusite-(Ca), ideally CaMn₂²⁺(PO₄)₂, a new graftonite-group mineral from the Yellowknife pegmatite field, Northwest Territories, Canada: Description and crystal structure