Scientists with the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) and Bar-Ilan University have discovered unusually high concentrations of silver in samples of many different types of pottery from excavations in Jerusalem of the late Second Temple period, the first century BCE (Before the Common Era) through 70 CE (Common Era). This is the first study ever conducted on silver in archaeological ceramics.
David Adan-Bayewitz, Associate Professor at Bar-Ilan in Ramat-Gan, Israel, and a guest at Berkeley Lab, and Frank Asaro and Robert D. Giauque of Berkeley Lab’s Environmental Energy Technologies Division made their discovery of performing measurements on 1,200 pottery vessels from 38 sites in Roman Judea (present-day Israel). They used high-precision X-ray fluorescence (HPXRF) and instrumental neutron activation analysis (INAA). The Berkeley Lab team developed a variation of INAA, the INAA coincidence technique, specifically for measuring silver concentrations in archaeological samples, as a more accurate means of checking the results of HPXRF and conventional INAA.
Hmmmm. They seem to be saying that the silver was post-depositionally inserted into the ceramics through groundwater, and that the silver came from objects stored underground by the wealthy inhabitants. Not sure how likely that is. Seems there'd have to be an wfully lot of silver exposed to groundwater for that to happen. Maybe the source clay or temper had silver in it? (but they say the samples with silver were only found in cities) So, eh.