Thermoluminescence Authenticity Measurements on Core Material From the Bronze Horse of the New York Metropolitan Museum of Art

Abstract

S The Bronze Horse of the Metropolitan Museum of Art, New York, suspected in recent years of being a modern forgery, is shown by thermoluminescence to have been made in antiquity. Besides the standard thermoluminescence measurements, a new technique was used, utilizing single, highly radioactive grains of zircon separated from the core material of the horse. The zircon grains, because of their high radioactivities (100–200 ppm) and subsequent large internal alpha doses (60–170 krad), are negligibly affected by γ irradiations given to the horse during previous examination. The results show the horse was made 2000 to 4000 years ago, consistent with a work of classical antiquity.

Fifty Years of Luminescence Dating*

“… A bronze horse, the antiquity of which was confirmed by comparing TL signals from fine grains and zircon grains extracted from remnants of the sand core used in the casting (from Zimmerman et al . 1974 ).…”

“…In a rare application, the equivalent doses of three zircon grains extracted from the sandy clay core remaining from the manufacture of a bronze horse of Greek or Roman age (Fig. 5) on show in the Metropolitan Museum of Art in New York were found to be several orders of magnitude larger than that obtained from the fine grains making up the bulk of the core (Zimmerman et al . 1974).…”

Archaeometry and Museums: Fifty Years of Curiosity and Wonder*

“…Other museum objects in brass have also been identified as modern by their Zn content (Craddock 1985; Al‐Saa'd 2000). More difficult to authenticate, the Metropolitan Museum Greek bronze horse was submitted to analysis (Lefferts et al 1981), including TL dating of the ceramic core material (Zimmerman et al 1974). Although it was deemed to be ancient, it was not possible to certify an Italian or Greek provenance using either accurate dating or isotopic analysis.…”

Robert M. Walker, 1929–2004

“…Bob's interests were wide-ranging and sometimes led to activities that exceeded the confines of his space-related scientific work. For example, the application of thermoluminescence led to the authentification of an ancient Greek bronze horse (e.g., Zimmerman et al 1974;Walker et al 1976), which in turn led to Bob's involvement in the preservation of artwork and, for several years, people worked on the restoration of sculptures in the middle of research on meteorites and lunar samples.…”