Intaglio engraved with a seated sphinx Brown and white zoned agate Roman art, 1st century BC - 1st century AD Size (intaglio): 1.2 x 0.9 cm 18th century silver mount Gross weight: 6.18g Bibliography : Die Antiken Gemmen, Geschischte der Steinschneidekunst im Klassischen Altertum, Aldolf Furtwängler, Leipzig-Berlin, 1900, pl. X, no. 58