Thermally induced cation redistribution in fluor-elbaite and Fe-bearing tourmalines

Bosi, Ferdinando; Skogby, Henrik; Hålenius, Ulf

doi:10.1007/s00269-018-1009-3

Cited by 15 publications

(15 citation statements)

References 45 publications

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“…This is manifested in various cation disorder reactions at octahedral sites. Along with the Al-Mg disorder Hawthorne et al 1993), the Cr-Al and V-Al disorder between Y and Z sites was documented (Bosi and Lucchesi 2004;Cempírek et al 2013;Bosi et al 2017), as well as disordering of Fe over Y and Z sites with temperature in treated samples (Bosi et al 2019). These were explained by several factors: the Fe/(Fe+Mg) ratio , influence of the W-site (Hawthorne 1996(Hawthorne , 2002 and X-site occupancy (Ertl et al 2010a), structural deformations (Foit 1989;Bosi and Lucchesi 2007), pressure (Ertl et al 2010b), and temperature (Bosi 2011).…”

Section: Crystal Chemistry Vs Genetic Environmentmentioning

confidence: 90%

Cation partitioning among crystallographic sites based on bond-length constraints in tourmaline-supergroup minerals

Bačík

Fridrichová

2021

American Mineralogist

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Theoretical bond-length calculations from ideal bond valences for each ion and coordination allow for the prediction of ion site preference and partitioning in tourmaline structures at low-pressure conditions. A comparison of calculated data with published bond-length values enables the determination of the range of structurally stable bond lengths with a minimal induced distortion—the “Goldilocks zone.” The calculations provided the following conclusions: the B-site occupancy is strictly limited to B3+; the T site can freely accommodate not only Si4+ but also B3+ and Al3+, although these substituents require shrinkage and expansion of the TO4 tetrahedron, respectively; and the Be2+ substitution results in a significant difference in charge. Satisfactory bond lengths for octahedral sites were calculated for Al3+ (Z-site preference), Ti4+, Mn3+, Ga3+, V3+, Fe3+ (mixed preference), Mg2+, Fe2+, Li+, Mn2+, Ni2+, Zn2+, Cu2+, Sc3+, and Zr4+ (Y-site preference). Another group of cations, which includes U4+, Th4+, Y3+, and lanthanoids from Tb to Lu and Ce4+, have significantly longer bonds than typical Y-O and very short bonds for the X site; therefore, it is likely they would prefer an octahedron. The empirical bond length for the X site is met with Na+, Ca2+, Sr2+, Pb2+, and lanthanoids from La to Gd, while K, Rb, and Cs are too large in the low-pressure conditions. However, the final tourmaline composition results from the interaction of the structure with the genetic environment in terms of P-T-X and geochemical conditions. This results in structural and environmental constraints that limit the incorporation of elements into the structure. Consequently, major elements, such as Si, Al, B, Mg, Fe, Na, and Ca usually occur in abundance, whereas other elements (V, Cr, Mn, Ti, Pb) could form end-member compositions, but rarely do because of their low abundance in the environment. The elements with contents limited to trace amounts have either structural (Be, C, REE, Rb, Cs, U, Th) or geochemical (Zr4+, Sc3+, and Sr2+) limits. However, environmental properties, such as high pressure or specific local structural arrangements, can overcome structural constraints and enable the incorporation of elements (K).

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Section: Crystal Chemistry Vs Genetic Environmentmentioning

confidence: 90%

Cation partitioning among crystallographic sites based on bond-length constraints in tourmaline-supergroup minerals

Bačík

Fridrichová

2021

American Mineralogist

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“…Moreover, the low variability of counts, verified by measurements on uniform matrix materials such as that of NIST glass samples, allowed us to perform measurements on tourmaline samples which normally have chemical zoning. The calibration, obtained using spectra recorded on two NIST standard glasses (SRM 610 and 612) and four Li-bearing tourmalines from Bosi et al (2005), Filip et al (2012), Grew et al (2018) and Bosi et al (2019d), resulted in two calibration curves: one below and the other above 0.1 Li 2 O wt.% (Fig. 3).…”

Section: Electron Microprobe Analysis (Empa)mentioning

confidence: 99%

“…The calibration resulted in two branches (one below and the other above 0.1 Li 2 O wt.%) described by two regression lines. Black squares represent samples from NIST standard glasses (SRM 610 and 612) and Filip et al (2012), black circles are from Bosi et al (2005, 2019d) and Grew et al (2018); and a red filled circle represents the present sample.…”

Section: Electron Microprobe Analysis (Empa)mentioning

confidence: 99%

Mn-bearing purplish-red tourmaline from the Anjanabonoina pegmatite, Madagascar

Bosi

Celata

Skogby

et al. 2021

MinMag

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A gem-quality purplish-red tourmaline sample of alleged liddicoatitic composition from the Anjanabonoina pegmatite, Madagascar, has been fully characterised using a multi-analytical approach to define its crystal-chemical identity. Single-crystal X-ray diffraction, chemical and spectroscopic analysis resulted in the formula: X(Na0.41□0.35Ca0.24)Σ1.00Y(Al1.81Li1.00Fe3+0.04Mn3+0.02Mn2+0.12Ti0.004)Σ3.00ZAl6 [T(Si5.60B0.40)Σ6.00O18] (BO3)3 (OH)3W[(OH)0.50F0.13O0.37]Σ1.00 which corresponds to the tourmaline species elbaite having the typical space group R3m and relatively small unit-cell dimensions, a = 15.7935(4) Å, c = 7.0860(2) Å and V = 7.0860(2) Å3. Optical absorption spectroscopy showed that the purplish-red colour is caused by minor amounts of Mn3+ (Mn2O3 = 0.20 wt.%). Thermal treatment in air up to 750°C strongly intensified the colour of the sample due to the oxidation of all Mn2+ to Mn3+ (Mn2O3 up to 1.21 wt.%). Based on infrared and Raman data, a crystal-chemical model regarding the electrostatic interaction between the X cation and W anion, and involving the Y cations as well, is proposed to explain the absence or rarity of the mineral species ‘liddicoatite’.

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“…with a delay of 2 μs after the second pulse and were integrated for 1 ms. Quantitative data were obtained by generating a linear regression using the main Li emission line intensity (670.706 nm corresponding to resonance transition 1s 2 2s > 1s 2 2p), which is particularly sensitive to Li amounts. The linear fit was made using spectra recorded on two NIST standard glasses (SRM 610 and 612) and three Li-bearing tourmaline samples from Filip et al (2012), Grew et al (2018) and Bosi et al (2019d). The result corresponds to 0.42 wt% of Li 2 O (Table 4).…”

Section: Micro-laser Induced Breakdown Spectroscopymentioning

confidence: 99%

Celleriite, ☐(Mn22+Al)Al6(Si6O18)(BO3)3(OH)3(OH), a new mineral species of the tourmaline supergroup

Bosi

Pezzotta²,

Altieri

et al. 2022

American Mineralogist

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Celleriite, (Mn 2+ 2 Al)Al 6 (Si 6 O 18 )(BO 3 ) 3 (OH) 3 (OH), is a new mineral of the tourmaline supergroup. It was discovered in the Rosina pegmatite, San Piero in Campo, Elba Island, Italy (holotype specimen) and in the Pikárec pegmatite, western Moravia, Czech Republic This is the peer-reviewed, final accepted version for American Mineralogist, published by the Mineralogical Society of America. The published version is subject to change. Cite as Authors (Year) Title. American Mineralogist, in press.

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Thermally induced cation redistribution in fluor-elbaite and Fe-bearing tourmalines

Cited by 15 publications

References 45 publications

Cation partitioning among crystallographic sites based on bond-length constraints in tourmaline-supergroup minerals

Cation partitioning among crystallographic sites based on bond-length constraints in tourmaline-supergroup minerals

Mn-bearing purplish-red tourmaline from the Anjanabonoina pegmatite, Madagascar

Celleriite, ☐(Mn22+Al)Al6(Si6O18)(BO3)3(OH)3(OH), a new mineral species of the tourmaline supergroup

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