Prossima pubblicazione.
Referenza:
▪ Haring, M.M.M. & McDonald, A.M. (2017): Charleshatchettite, CaNb4O10(OH)2·8H2O, a new mineral from Mont Saint-Hilaire, Québec, Canada: Description, Crystal-Structure Determination and Origin. American Mineralogist, 102, (in press).
IMA 2015-048 = charleshatchettite
- Marco E. Ciriotti
- Messaggi: 31675
- Iscritto il: ven 25 giu, 2004 11:31
- Località: via San Pietro, 55 I-10073 Devesi/Cirié TO - Italy
- Contatta:
IMA 2015-048 = charleshatchettite
Marco E. Ciriotti
«Things are interesting only in so far as they relate themselves to other things»
«Things are interesting only in so far as they relate themselves to other things»
Re: IMA 2015-048 = charleshatchettite
La "hatchettite" è stata discreditata come specie?
Michiel Desittere
Benedetti siano gli istanti
e i millimetri
e le ombre delle piccole cose.
(Fernando Pessoa)
Benedetti siano gli istanti
e i millimetri
e le ombre delle piccole cose.
(Fernando Pessoa)
- Marco E. Ciriotti
- Messaggi: 31675
- Iscritto il: ven 25 giu, 2004 11:31
- Località: via San Pietro, 55 I-10073 Devesi/Cirié TO - Italy
- Contatta:
Re: IMA 2015-048 = charleshatchettite
La "hatchettite" è una paraffina mai approvata come specie minerale.
Potrebbe essere identica alla evenkite, C21H44.
Potrebbe essere identica alla evenkite, C21H44.
Marco E. Ciriotti
«Things are interesting only in so far as they relate themselves to other things»
«Things are interesting only in so far as they relate themselves to other things»
Re: IMA 2015-048 = charleshatchettite
Grazie Marco. La pagina Mindat riporta, per la hatchettite:Marco E. Ciriotti ha scritto: ↑mer 19 lug, 2017 22:03La "hatchettite" è una paraffina mai approvata come specie minerale.
Potrebbe essere identica alla evenkite, C21H44.
"IMA status:Approved, 'Grandfathered' (first described prior to 1959), Questionable"
Michiel Desittere
Benedetti siano gli istanti
e i millimetri
e le ombre delle piccole cose.
(Fernando Pessoa)
Benedetti siano gli istanti
e i millimetri
e le ombre delle piccole cose.
(Fernando Pessoa)
- Marco E. Ciriotti
- Messaggi: 31675
- Iscritto il: ven 25 giu, 2004 11:31
- Località: via San Pietro, 55 I-10073 Devesi/Cirié TO - Italy
- Contatta:
Re: IMA 2015-048 = charleshatchettite
Errore!La pagina Mindat riporta, per la hatchettite:
"IMA status:Approved, 'Grandfathered' (first described prior to 1959), Questionable"
Vedo di correggerla.
Marco E. Ciriotti
«Things are interesting only in so far as they relate themselves to other things»
«Things are interesting only in so far as they relate themselves to other things»
- Marco E. Ciriotti
- Messaggi: 31675
- Iscritto il: ven 25 giu, 2004 11:31
- Località: via San Pietro, 55 I-10073 Devesi/Cirié TO - Italy
- Contatta:
Re: IMA 2015-048 = charleshatchettite
Pubblicazione effettuata.
Referenza:
▪ Haring, M.M.M. & McDonald, A.M. (2017): Charleshatchettite, CaNb4O10(OH)2·8H2O, a new mineral from Mont Saint-Hilaire, Québec, Canada: Description, Crystal-Structure Determination and Origin. American Mineralogist, 102, 2333–2340.
Abstract:
Charleshatchettite, CaNb4O10(OH)2·8H2O, is a new mineral related to franconite and hochelagaite, discovered on a fracture surface of a nepheline syenite at Mont Saint-Hilaire, Québec, Canada. The mineral occurs in white globules (~0.15–0.20 mm in diameter) composed of radiating crystals with individual crystals having average dimensions of ~0.002 × 0.010 × 0.040 mm. Crystals are euhedral, bladed (flattened on [100]), and are transparent to translucent. The mineral is associated with albite, quartz, muscovite, pyrrhotite, pyrite, ancylite-(Ce), and siderite. Charleshatchettite is inferred to be biaxial (–) with α′ = ~1.72(2) and γ′ = ~1.82(2). Data from chemical analyses (SEM-EDS, n = 8): CaO 7.96 (7.04–8.63), MgO 0.24 (0.08–0.78), Al2O3 0.13 (b.d.–0.49), SiO2 1.04 (0.49–1.88), TiO2 3.64 (2.45–5.05), Nb2O5 68.07 (64.83–71.01), and H2O (calc) 22.96, total 104.04 wt% gives the average empirical formula: (Ca1.00Mg0.04)Σ1.04(Nb3.62Ti0.32Si0.12Al0.02)Σ4.08O10(OH)2·8H2O (based on 20 anions). This is similar to that of hochelagaite (CaNb4O11·nH2O), although the two are readily distinguished by their powder X‑ray diffraction patterns. Results from single-crystal X‑ray diffraction analysis give a = 21.151(4), b = 6.496(2), c = 12.714(3) Å, and β = 103.958(3)°, space group C2/c (no. 15). The crystal structure, refined to R = 5.64%, contains 1 Ca site, 2 distorted octahedral Nb sites, and 10 O sites. It consists of clusters of four edge-sharing Nb(O,OH)6 octahedra, linked through shared corners to adjacent clusters, forming layers of Nb(O,OH)6 octahedra. These alternate along [100] with layers composed of Ca(H2O)8 polyhedra, the two being linked together by H-bonding. Charleshatchettite is a late-stage mineral, interpreted to have developed through the interaction of low-T (<150 °C) aqueous fluids with an alkali-, Nb-rich precursor under slightly reducing conditions and a highly alkaline pH. The precursor mineral(s) is unknown but is considered to have been Nb-dominant, relatively unstable under slightly reducing as well as alkaline conditions, and likely itself would have been a product of near-complete Nb/Ta fractionation due to the paucity of Ta in charleshatchettite. Charleshatchettite is crystallochemically related to Sandia Octahedral Molecular Sieves [SOMS; Na2Nb2–xMxO6–x(OH)x·H2O with M = Ti, Zr, Hf], a group of synthetic compounds with strong ion exchange capabilities.
Referenza:
▪ Haring, M.M.M. & McDonald, A.M. (2017): Charleshatchettite, CaNb4O10(OH)2·8H2O, a new mineral from Mont Saint-Hilaire, Québec, Canada: Description, Crystal-Structure Determination and Origin. American Mineralogist, 102, 2333–2340.
Abstract:
Charleshatchettite, CaNb4O10(OH)2·8H2O, is a new mineral related to franconite and hochelagaite, discovered on a fracture surface of a nepheline syenite at Mont Saint-Hilaire, Québec, Canada. The mineral occurs in white globules (~0.15–0.20 mm in diameter) composed of radiating crystals with individual crystals having average dimensions of ~0.002 × 0.010 × 0.040 mm. Crystals are euhedral, bladed (flattened on [100]), and are transparent to translucent. The mineral is associated with albite, quartz, muscovite, pyrrhotite, pyrite, ancylite-(Ce), and siderite. Charleshatchettite is inferred to be biaxial (–) with α′ = ~1.72(2) and γ′ = ~1.82(2). Data from chemical analyses (SEM-EDS, n = 8): CaO 7.96 (7.04–8.63), MgO 0.24 (0.08–0.78), Al2O3 0.13 (b.d.–0.49), SiO2 1.04 (0.49–1.88), TiO2 3.64 (2.45–5.05), Nb2O5 68.07 (64.83–71.01), and H2O (calc) 22.96, total 104.04 wt% gives the average empirical formula: (Ca1.00Mg0.04)Σ1.04(Nb3.62Ti0.32Si0.12Al0.02)Σ4.08O10(OH)2·8H2O (based on 20 anions). This is similar to that of hochelagaite (CaNb4O11·nH2O), although the two are readily distinguished by their powder X‑ray diffraction patterns. Results from single-crystal X‑ray diffraction analysis give a = 21.151(4), b = 6.496(2), c = 12.714(3) Å, and β = 103.958(3)°, space group C2/c (no. 15). The crystal structure, refined to R = 5.64%, contains 1 Ca site, 2 distorted octahedral Nb sites, and 10 O sites. It consists of clusters of four edge-sharing Nb(O,OH)6 octahedra, linked through shared corners to adjacent clusters, forming layers of Nb(O,OH)6 octahedra. These alternate along [100] with layers composed of Ca(H2O)8 polyhedra, the two being linked together by H-bonding. Charleshatchettite is a late-stage mineral, interpreted to have developed through the interaction of low-T (<150 °C) aqueous fluids with an alkali-, Nb-rich precursor under slightly reducing conditions and a highly alkaline pH. The precursor mineral(s) is unknown but is considered to have been Nb-dominant, relatively unstable under slightly reducing as well as alkaline conditions, and likely itself would have been a product of near-complete Nb/Ta fractionation due to the paucity of Ta in charleshatchettite. Charleshatchettite is crystallochemically related to Sandia Octahedral Molecular Sieves [SOMS; Na2Nb2–xMxO6–x(OH)x·H2O with M = Ti, Zr, Hf], a group of synthetic compounds with strong ion exchange capabilities.
Marco E. Ciriotti
«Things are interesting only in so far as they relate themselves to other things»
«Things are interesting only in so far as they relate themselves to other things»
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