Please use this identifier to cite or link to this item:
Title: Colours of Gemmy Phosphates from the Gavà Neolithic Mines (Catalonia, Spain): Origin and Archaeological Significance
Authors: Díaz‐Acha, Yael
Campeny, Marc
Casas, Lluís
Di Febo, Roberta
Ibañez-Insa, Jordi
Jawhari, Tariq
Bosch, Josep
Borrell, Ferran
Jorge-Villar, Susana E.
Greneche, Jean-Marc
Tauler, Esperança
Melgarejo, Joan Carles
Keywords: Colour;Variscite;Turquoise;Phosphates;Neolithic mines;Gavà
Issue Date: Mar-2022
Publisher: MDPI
Citation: Minerals 2022, 2022, 12(3), 368
Abstract: In the Neolithic Gavà mines, variscite and turquoise were exploited for ornaments manufacturing, although some prospective pits and tunnels were dug on other similar greenish minerals such as smectite or kandite. A 3D study of the distribution of mineral phases allows us to determine the parameters involved in variscite colours. Methods are comprised of quantitative colourimetry, thin section petrography, SEM-BSE-EDS, EMPA, XRD, Raman spectroscopy, and 57Fe Mössbauer spectrometry. Mapping of the mines indicates that colour is not directly dependent on depth. Although variscite from Gavà is poor in Cr3+ and V+3 compared with gemmy variscite from other localities, the deep green samples content has the highest values of Cr3+. In the case of cryptocrystalline mixtures with jarosite, phosphosiderite, or goethite, variscite tends to acquire a greenish brown to olivaceous hue. If white minerals such as quartz, kandite, crandallite, or alunite are involved in the mixtures, variscite and turquoise colours become paler.
ISSN: 2075-163X
DOI: 10.3390/min12030368
Editor version:
Type: Article
Appears in Collections:Arqueometría
Geocronología y Geología

This item is licensed under a Creative Commons License Creative Commons