The recent study conducted by IGE on the custody of Toledo Cathedral was brilliantly presented during an online webinar by Egor Gavrilenko, a doctor and gemologist, and Marta Esteban, gemologist, expert in diamond and colored stones classification.
The so-called “Custodia de Arfe” is a masterpiece by the goldsmith Enrique de Arfe, created between 1515 and 1523, which also includes the portable Monstrance from the late 15th century that belonged to Queen Isabella the Catholic, a work of the Barcelona silversmith Jaume Aimeric. The custody has an invaluable value both as an object of worship and as a testimony to the history of art, goldsmithing, and gemology.
The authors conducted a comprehensive gemological study of the custody, commissioned by IGE (the Spanish Gemological Institute), which included the identification and description of all the precious stones used in the decoration of the custody (472 in total). The work was carried out as part of the custody conservation and restoration project, organized by the Chapter of Toledo Cathedral and the Cultural Heritage Institute of Spain. The detailed results of this study have recently been published as a chapter in the book dedicated to the overall conservation and restoration project of the custody (ISBN: 978-84-8181-846-8).
The gemological analysis was conducted on mounted gems, in the spaces of Toledo Cathedral, using traditional and advanced gemological techniques, including Raman spectroscopy and estimation of gem weight through 3D modeling and photogrammetry. All the gems were identified, their quality grades described, and in some cases even their geographic origin. Among the results, the star sapphire from Sri Lanka of over 100 carats and the numerous Colombian emeralds stand out for their size and quality. Another aspect to highlight is the total absence of glass and imitations, a common phenomenon in many historical artifacts.
