Portrait of a Goldsmith, Probably Bartholomeus Jansz van Assendelft, Werner van den Valckert, 1617
The man leans out of a window. In his right hand he holds up a gold ring set with a stone. His left hand rests on a touchstone, an instrument for assessing the purity of gold and silver objects. The sitter might be the goldsmith Bartholomeus Jansz van Assendelft. In 1617, the year the portrait was painted, he was appointed assay-master of the Leiden goldsmiths’ guild, which would explain the inclusion of the touchstone.