A RARE ROCKCRYSTAL OBJECT FROM POMPEII 29 Abstract A Rare Rock-Crystal Object from Pompeii A Furniture Inlay, a Medical Instrument, a Magnifying Lens or a Gaming Piece? BY DOMINIC INGEMARK Ingemark, Dominic. 2011. A Rare Rock-Crystal Object from Pompeii: A Furniture Inlay, a Medical Instrument, a Magnifying Lens or a Gaming Piece? Lund Archaeological Review 16 (2011), pp. 29–33. The aim of this paper is to discuss the function of a small – 16 mm in diameter and 7 mm high – lathe-turned object in rock crystal. This is an object in a material that was regarded as very valuable and belongs to a relatively rare category of finds, but what merits discussion concerning its function is the fact that it is a true lens. As no definitive answer as to its function can be given, a number of hypothetical possibilities are presented: that it was a furniture inlay; that it functioned as a burning glass for medical purposes; that it was a magnifying aid used in the manufacture of gems and suchlike objects; that it was a magnifying aid employed when writing and/or reading, or that it was a magnifying gaming piece that was used for playing a specific type of board game. Of the different solutions presented, the suggestion that it was a gaming piece seems most likely. Dominic Ingemark, Department of Archaeology and Ancient History, Lund University, Sand- gatan 1, 223 50 Lund. Dominic.Ingemark@klass.lu.se. Introduction Among numerous other nds yielded by the excavations in Insula V.1 by the Swedish Pom- peii Project is a small nd that is of special interest: a lathe-turned plano-convex object in rock crystal from a small taberna (V.1, 27) which was used for dyeing cloth in. It is of relatively small size, approximately 16 mm in diameter and 7 mm high (Fig. 1). Rock crys- tal was a much appreciated material in Roman times; indeed it was regarded as very valuable (Pliny the Elder, Natural History, 37.204). It is not the value of this object that attracts attention, however, but rather its shape and possible function. For what makes it interes- ting is that it is a true lens, regardless of what function the object may originally have had. Jay M. Enoch – professor of optometry at University of California, Berkeley – has put forward the following denition of a lens in a publication concerning the function of lenses from antiquity: e lens material must be acceptably transparent and homogeneous, and surfaces must be reasona- bly regular. At least one surface must be curved, and surface irregularities must be modest. ere should be a principal axis for the two surfaces, and the lens must be able to form an adequate image (Enoch 1998, p. 275). e nd from Pompeii complies with this denition: the rock crystal is perfectly trans- parent and free from any form of aws; the quality of the craftsmanship is high, the ob- ject being perfectly cut, and the object creates a good image (Fig. 2).