From mastodon ivory to gemstone: The origin of turquoise color in odontolite - CNRS - Centre national de la recherche scientifique Accéder directement au contenu
Article Dans Une Revue The American Mineralogist Année : 2001

From mastodon ivory to gemstone: The origin of turquoise color in odontolite

Résumé

Heat-induced color changes of fossilized Miocene mastodon ivory (13-16 Ma) have been known at least since the Middle Ages. Cistercian monks are believed to have created odontolite, a turquoise- blue “gemstone,” by heating mastodon ivory found in Miocene geological layers next to the Pyrrenean chain, France, to use it for the decoration of medieval art objects. This material has been the object of investigations of famous European naturalists and gemmologists, among them Réaumur (1683-1757). Although vivianite [Fe3(PO4)2·8H2O] is the commonly accepted coloring phase supposed to appear when heating fossilized mastodon ivory, our previous spectroscopic studies using PIXE/PIGE and TEM-EDX demonstrated that the chemical composition of collection odontolite and heated mastodon ivory corresponds to well-crystallized fluorapatite [Ca5(PO4)3F] containing trace amounts of Fe (230-890 ppm), Mn (220-650 ppm), Ba (160-620 ppm), Pb (40-140 ppm), and U (80-210 ppm). No vivianite has been detected.

Domaines

Chimie
Fichier non déposé

Dates et versions

hal-04258114 , version 1 (25-10-2023)

Identifiants

Citer

Ina Reiche, Colette Vignaud, Bernard Champagnon, Gérard Panczer, Christian Brouder, et al.. From mastodon ivory to gemstone: The origin of turquoise color in odontolite. The American Mineralogist, 2001, 86 (11-12), pp.1519-1524. ⟨10.2138/am-2001-11-1221⟩. ⟨hal-04258114⟩
12 Consultations
0 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More