Objective characterization of jewels in paintings, especially pearls, has been a long lasting challenge for art historians. The way an artist painted pearls reflects his ability to observe nature and his acquaintance with contemporary optical theory. Moreover, the painterly execution may also be considered as an individual characteristic, useful in distinguishing hands. In this contribution, we propose a set of image analysis techniques to analyze and measure spatial characteristics of the digital images of pearls and beads, all relying on the so called spatiogram image representation. Our experimental results demonstrate a good correlation between the new metrics and the visually observed image features, and also capture the degree of realism of the visual appearance in the painting. In that sense, these results set the basis in creating a practical tool for art historical analysis and attribution and provide strong motivation for further investigations in this direction.