Nearly 200 glass beads were analyzed by x-ray fluorescence. Most were of Anglo-Saxon date but some were Roman and some medieval. The analytical results are not fully quantitative but can be displayed graphically to show variations in composition that correlate well with visible differences in the appearance of the glass. Some beads that look the same have different compositions, which suggest multiple origins for them. The analyses were not intended to determine major element compositions but to identify minor elements, mainly colorants, decolorizers and opacifiers to demonstrate continuity and change in their use. The elements determined were titanium, manganese, iron, cobalt, nickel, copper, zinc, lead arsenic, tin and antimony.