A gemmological study of the reliquary crown of Namur, Belgium

Abstract

Abstract. The reliquary crown, hosted in the diocesan museum of Namur, was produced during the beginning of the 13th century to shelter a fragment of the holy crown of thorns. This beautiful piece of goldsmithery is made of eight gold plates, topped by round lobes, and connected to each other by hinges blocked with a pin decorated by a pearl. The crown is decorated by filigrees, flowers, and approximately 400 pearls and coloured (green, reddish pink, turquoise, red, blue) stones showing simple cutting with various sizes and shapes. Raman and portable X-ray fluorescence spectrometer (pXRF) techniques have been used to determine the nature and sources of all samples, as well as the composition of filigrees. Analyses have identified emeralds from Pakistan, reddish pink spinels from Tajikistan, red almandine garnets from India, turquoise from Iran, blue sapphires from Sri Lanka or Myanmar, and European pearls. The filigrees contain approximately 86 wt % Au, 7 wt % Ag, and 7 wt % Cu, thus confirming a gold-rich composition. The gemstones, contemporary with the crown, probably arrived in Europe by the silk trade road.

An Archaeometric Investigation of Gems and Glass Beads Decorating the Double-Arm Reliquary Cross from Liège, Belgium

“…The green, blue, and amber stones show Raman spectra characterized by very large bands, located around 300-600 cm −1 (symmetric bending of SiO 4 tetrahedra) and 900-1300 cm −1 (Si-O stretching vibrations) [8]. These spectra are characteristic of amorphous glass material, as frequently observed in medieval goldsmithery items [4][5][6].…”

“…The green, blue, and amber stones show Raman spectra characterized by very large bands, located around 300-600 cm −1 (symmetric bending of SiO4 tetrahedra) and 900-1300 cm −1 (Si-O stretching vibrations) [8]. These spectra are characteristic of amorphous glass material, as frequently observed in medieval goldsmithery items [4][5][6]. The green, blue, and amber stones show Raman spectra characterized by very large bands, located around 300-600 cm −1 (symmetric bending of SiO 4 tetrahedra) and 900-1300 cm −1 (Si-O stretching vibrations) [8].…”

“…The interest of analysing ancient goldsmiths' artwork using modern archaeometric methods has increased recently, as shown by the recent Raman and XRF investigations of the reliquary from Lierneux [4], of the "Sainte-Épines" crown from Namur [5], and of the reliquary-bust of Saint Lambert from Liège [6]. The reliquary cross investigated herein was previously analysed by Demaude [2] using portable Raman spectrometer and qualitative p-XRF.…”