Dacostaite, K(Mg2Al)[Mg(H2O)6]2(AsO4)2F6.2H2O, a new fluoride-arsenate mineral from the Cetine di Cotorniano mine (Tuscany, Italy)

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00023272%3A_____%2F25%3A10136967" target="_blank" >RIV/00023272:_____/25:10136967 - isvavai.cz</a>

Alternative codes found

RIV/00216224:14310/25:00140751

Result on the web

<a href="https://ejm.copernicus.org/articles/37/39/2025/ejm-37-39-2025.pdf" target="_blank" >https://ejm.copernicus.org/articles/37/39/2025/ejm-37-39-2025.pdf</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.5194/ejm-37-39-2025" target="_blank" >10.5194/ejm-37-39-2025</a>

Result language

angličtina

Original language name

Dacostaite, K(Mg2Al)[Mg(H2O)6]2(AsO4)2F6.2H2O, a new fluoride-arsenate mineral from the Cetine di Cotorniano mine (Tuscany, Italy)

Original language description

The new mineral dacostaite, K(Mg2Al)[Mg(H2O)6]2(AsO4)2F6.2H2O, has been discovered in the Cetine di Cotorniano Mine, Chiusdino, Siena, Tuscany, Italy. It occurs as thin, colourless-to-white pseudo-hexagonal micaceous crystals up to 0.5 mm in size. The streak is white, and the lustre is silky. The cleavage is perfect on {001}. The empirical formula of dacostaite, based on (As + P) = 2 atoms per formula unit, is (K0.56Ca0.04Na0.03square0.37)Σ1.00(Al1.54Mg1.38Cu0.03Zn0.03)Σ2.98[Mg(H2O)6]2[(As0.99P0.01O4]2[F4.46(OH)(1.46)O0.08](Σ6.00).2H2O (Z=2). Dacostaite is monoclinic, with a space group of C2/m and a=12.474(5), b=7.198(3), c=13.724(6) Å, beta=99.518(13)degrees, and V=1215.3(8) Å3. The crystal structure was solved using single-crystal X-ray diffraction data and refined to R1=0.0927 for 1022 unique reflections with F-o&gt;4 sigma(F-o). The crystal structure of dacostaite can be described as formed by heteropolyhedral {001} layers and isolated Mg(H2O)6 groups connected by H bonds. In the type material, dacostaite is associated with quartz, sulfur, gypsum, and a pharmacosiderite-like mineral in a small cavity of silicified limestone. Its genesis is related to the activity of oxidized (Al,F)-rich fluids during the late-stage evolution of the Sb ore deposit formerly exploited at the Cetine di Cotorniano Mine.

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

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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

European Journal of Mineralogy

ISSN

0935-1221

e-ISSN

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Volume of the periodical

37

Issue of the periodical within the volume

1

Country of publishing house

DE - GERMANY

Number of pages

14

Pages from-to

39-52

UT code for WoS article

001400555700001

EID of the result in the Scopus database

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