Tibetan silver (Chinese Zangyin) in modern usage refers to a variety of white non-precious metal alloys used primarily in jewelry components, with an appearance similar to aged silver.
Silver was imported from China (as ingots), India (tankas), and from Mongolia and Siberia.
[1] In addition to coinage silver was used in Tibet for repousse work, and as an inlay in brass and copper statues.
An X-ray fluorescence analysis showed that six of seven items acquired online and described as 'Tibetan silver' were alloys containing primarily copper, nickel, zinc.
[3] Zangyin is a Chinese term for 'Tibetan silver' - it seems to originate from a scholar's term for the inferior silver adulterated with high proportion of copper used for Tibetan coinage in the late Qing dynasty period.