Some examples of Longquan greenware have been analyzed by neutron activation analysis. Most sherds are from kiln excavations in Zhejiang province, and date from the Song, Yuan, and Ming dynasties. The elements cesium, ytterbium, hafnium, and tantalum are shown to be consistently high and suggest that a common clay was used over a long period. The iron content of the glaze is shown to decrease from the Song to the Ming dynasty, implying an improvement in the refiring of the glaze raw materials. See also AATA 21-1967 and 21-2029 for additional studies of Longquan glazes. -- AATA