Four beakers or two beakers? Only your conservator knows for sure…

Stephen P. Koob


Fragments of four glass beakers were acquired by the Corning Museum of Glass in 1964 and 1967, and after reassembly, were catalogued. Over 30 years later, after numerous efforts and re-examination, the fragments were disassembled and reconsidered. Through careful microscopic examination using reflected and transmitted light, it was determined that the four catalogued sections actually made two vessels.

The beakers are made of very thin (0.5 mm – 1.2 mm) dark cobalt blue glass, which is transparent under transmitted light. The beakers were scratch-engraved, enameled and gilded, with decoration consisting of three bands of roundels, each of which contains a hawk or bird-of-prey. Unfortunately most of the enamel and gilding is now lost, and only traces remain. The beakers are attributed to the late 12th- early 13th centuries and were most likely made in the eastern Mediterranean, in territory controlled by the Byzantine empire.

It was through repeated examination and re-assembly that it was discovered two of the four catalogued sections probably belonged together. This was finally proven correct when air bubbles and traces of the dark cobalt streaks in the glass were lined up, using transmitted light microscopy. This also confirmed the order in which the roundel decoration was done, and it was found to repeat for all three bands.

The fragments were finally completely assembled, using detachable intermediary plaster restorations, from which detachable epoxy fills were made. Two new joins were discovered, and fragments previously not included in the restorations were added.

Once the first beaker was completed, it was then possible to determine that the other two catalogued sections actually formed one object as well. The bands of decoration were mapped out, and even though the second beaker was much more fragmentary, it was possible to restore this one as well, using the same restoration techniques.

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2002 | Miami | Volume 9