Ferro-bosiite, NaFe3+3(Al4Fe2+2)(Si6O18)(BO3)3(OH)3O, a new mineral species of the tourmaline supergroup

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216224%3A14310%2F25%3A00143169" target="_blank" >RIV/00216224:14310/25:00143169 - isvavai.cz</a>

Result on the web

<a href="https://doi.org/10.1180/mgm.2025.10114" target="_blank" >https://doi.org/10.1180/mgm.2025.10114</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1180/mgm.2025.10114" target="_blank" >10.1180/mgm.2025.10114</a>

Result language

angličtina

Original language name

Ferro-bosiite, NaFe3+3(Al4Fe2+2)(Si6O18)(BO3)3(OH)3O, a new mineral species of the tourmaline supergroup

Original language description

Ferro-bosiite, NaFe3+3(Al4Fe2+2)(Si6O18)(BO3)3(OH)3O, is a new mineral of the tourmaline supergroup. It was found in a giant collapsed cavity discovered in the Marina granitic pegmatite, at the Mavuco locality, Alto Ligonha, Mozambique. Ferro-bosiite occurs as a black acicular late-stage overgrowth at the analogous pole of a multicoloured fluor-elbaite crystal. The black crystals, with a vitreous lustre, have a brown streak, conchoidal fracture and a Mohs hardness of ∼7. Ferro-bosiite is uniaxial (–), with refractive indices ω = 1.675(5) and ε = 1.645(5). It has trigonal symmetry, space group R3m, a = 16.0499(5) Å, c = 7.2977(2) Å, V = 1628.03(11) Å3, Z = 3 and calculated density = 3.216 g/cm3. The crystal structure was refined to R1 = 2.55% using 1547 unique reflections collected with MoKα X-ray intensity data. Crystal-chemical analysis resulted in the empirical crystal-chemical formula: X(Na0.99K0.02)Σ1.01Y(Fe3+1.56V3+0.02Mg1.01Fe2+0.20Mn2+0.03Ti0.16Li0.02)Σ3.00Z(Al4.32Fe3+0.41Fe2+1.22Mg0.05)Σ6.00T[(Si5.99Al0.01)Σ6.00O18] (BO3)3O(3)(OH)3O(1)[O0.62(OH)0.34F0.04]Σ1.00. Ferro-bosiite is an oxy-species belonging to alkali group 3 of the tourmaline supergroup. It is related to bosiite by the substitution ZFe2+ ↔ ZMg. The new mineral has been approved by the International Mineralogical Association’s Commission on New Minerals, Nomenclature and Classification (IMA 2020-069). Ferro-bosiite forms part of a continuous solid-solution trend from Fe3+-rich oxy-dravite to dutrowite, driven by increasing Fe3+ and Ti, and X-site vacancies. At its type locality, ferro-bosiite formed during late-stage interaction with B-rich hydrothermal fluids that became enriched in Fe and Mg, probably due to a distinct fluid phase active after the collapse of a giant cavity.

Czech name

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Czech description

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Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

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OECD FORD branch

10504 - Mineralogy

Project

—

Continuities

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2025

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

MINERALOGICAL MAGAZINE

ISSN

0026-461X

e-ISSN

1471-8022

Volume of the periodical

89

Issue of the periodical within the volume

6

Country of publishing house

GB - UNITED KINGDOM

Number of pages

11

Pages from-to

886-896

UT code for WoS article

001617649800001

EID of the result in the Scopus database

2-s2.0-105012584375