Coin weights are weights used to weigh precious-metal coins in order to assure they were not underweight (It is easy to shave a bit of metal off the edge of a silver or gold coin).
[1] The usage of coin weights, especially glass ones, goes back to Ptolemaic and Byzantine times.
[1] Islamic coin weights were made of bronze, iron, and later glass (considered to be unalterable).
[1] They bear inscriptions related to Islamic rulers and moneyers and are therefore valuable epigraphical objects.
[3] Islamic coin weights were introduced to Great Britain in the 9-10th century CE through the Vikings.