Transparent gold ruby. Mold-blown, engraved, cut; gilded silver mount. Cylindrical beaker with flat base. Band of gilded silver around bottom, with three feet in shape of claw, each mounted with blown hollow, ribbed ball, and with silver floral disks below. Domed cover has gadrooned silver rim. Hollow, ribbed ball finial, surmounted by disk pedestal and realistically cast eagle with spread wings. On base mount, Augsburg assay mark and indecipherable maker’s mark. Near base, band of cut ovals framed with dotted borders and foliate sprays; above, three engraved swags of fruit, each with bird. On bottom, polished pontil mark surrounded by ring of engraved dots separated with sprigs. On cover, three engraved bunches of fruit joined by foliate sprays.

Johann Kunckel (about 1632-1703) invented gold ruby glass between 1678 and 1685. Friedrich Wilhelm III, elector of Brandenburg, supported this German scholar and chemist in his attempts to develop new varieties of luxury glass at the glasshouse in Potsdam-Drewitz, near Berlin. There, Kunckel made gold ruby glasses using a complex process that required a separate furnace and expensive raw materials. As a reward for his success, the elector gave him Peacock Island on the river Havel, where Kunckel built his own glassworks in 1685. This factory was destroyed by fire three years later, and Kunckel’s glassmaking career never revived. Although gold ruby glass was always a luxury, it was soon being made by other glasshouses. One of them was located in southern Germany, possibly around Nuremberg, but its exact location has not been identified. The deep color of gold ruby glasses provided a fine background for bold cutting and restrained engraving.