Egor Gavrilenko and Marta Esteban, gemmologists and former directors of the Gemological laboratory of the IGE (Instituto Gemológico Español) will be the speakers at the webinar dedicated to the gemmological study on the Monstrance of Arfe of the Toledo Cathedral, which will take place on 23 April 2024 at 7:30 pm (Madrid time).
The so-called “Custodia de Arfe”, also known as “La Gran Ostensoria de Toledo”, was made between 1515 and 1523 by Enrique de Arfe, a goldsmith of German origin, at the request of the Council of Toledo Cathedral to house the gold monstrance that belonged to Queen Isabel I of Castile, made by Jaume Aimeric. It is a portable case, which has a prismatic neck with niches housing the enamelled relief depictions of St. Sebastian, St. Christopher, St. Francis and the Virgin Mary: a small temple of six columns decotared with ears of corn, bunches of grapes and vine-shoots, adorned with precious stones and enamels. It is adorned with emeralds, garnets and pearls and is finished with a cross with straight arms studded with diamonds. At the top of this golden ostensory is a cylindrical dovecote containing enamelled doves and a large sapphire. The central key is decorated with an enamel and gemstone pendant and eighteen rosettes with cherub heads.
The authors carried out a comprehensive gemmological study of the monstrance, commissioned from the Spanish Gemmological Institute (IGE), which included the identification and description of all the precious stones used in the decoration (472 in total). The work was carried out as part of the project for the conservation and restoration of the artifact, organised by the Council of Toledo Cathedral and the Institute of Cultural Heritage of Spain. The detailed results of this study were recently published as a book chapter dedicated to the overall project of conservation and restoration of the monstrance (ISBN: 978-84-8181-846-8).
The gemmological analysis was carried out using traditional and advanced gemmological techniques, including Raman spectroscopy and gemstone weight estimation using 3D modelling and photogrammetry. All gems were identified, their quality grades were described and, in some cases, their geographical origin was also reported. The results highlight the remarkable variety, authenticity and quality of the gems used as glass and simulants, typical of many historical jewellery pieces, were not found.
The online webinar will detail the methods used and the results of the gemmological study of this great heritage jewel. Attendance is free of charge and registration can be made via the Zoom platform, directly from the website of the Instituto Gemológico Español.
