Dellagiustaite

a novel natural spinel containing V2+

Fernando Cámara*, Luca Bindi, Adriana Pagano, Renato Pagano, Sarah E. M. Gain, William L. Griffin

*Corresponding author for this work

Research output: Contribution to journalArticle

4 Citations (Scopus)
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Abstract

Dellagiustaite, ideally Al2V2+O4, is a new spinel-group mineral from Sierra de Comechingones, San Luis, Argentina, where it is found associated with hibonite (containing tubular inclusions, 5–100 μm, of metallic vanadium), grossite, and two other unknown phases with ideal stoichiometry of Ca2Al3O6F and Ca2Al2SiO7. A very similar rock containing dellagiustaite has been found at Mt Carmel (northern Israel), where super-reduced mineral assemblages have crystallized from high-T melts trapped in corundum aggregates (micro-xenoliths) within picritic-tholeiitic lavas ejected from Cretaceous volcanoes. In the holotype, euhedral grains of dellagiustaite are found as inclusions in grossite. The empirical average chemical formula of dellagiustaite is (Al1.09 V2+0.91V3+0.87 Mg0.08 Ti3+0.04 Mn0.01)Σ3O4, but it may show limited replacement of V2+ by Mg and of V3+ by Al. As Al is the dominant trivalent cation, the ideal formula is Al2V2+O4 according to the current IMA rules. Dellagiustaite shows the usual space group of spinel-group minerals (Fd 3¯ m, R1 = 1.46%) with a = 8.1950(1) Å. The observed mean bond lengths <T–O> = 1.782(2) Å and <M–O> = 2.0445(9) Å, the observed site scattering (T = 13.3 eps, M = 22.5 eps), and the chemical composition show that dellagiustaite is an inverse spinel: T tetrahedra are occupied by Al3+, whereas M octahedra are occupied by V2+ and V3+, leading to the site assignment as TAlM( V2+0.91V3+0.88Al3+0.09 Mg0.08 Ti3+0.03 Mn0.01)O4.

Original languageEnglish
Article number4
Pages (from-to)1-16
Number of pages16
JournalMinerals
Volume9
Issue number1
DOIs
Publication statusPublished - Jan 2019

Bibliographical note

Copyright the Author(s) 2018. Version archived for private and non-commercial use with the permission of the author/s and according to publisher conditions. For further rights please contact the publisher.

Keywords

  • dellagiustaite
  • spinel supergroup
  • oxyspinel subgroup
  • new mineral species
  • crystal structure
  • Sierra de Comechingones
  • Argentina
  • Mt Carmel
  • Israel

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