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] Coin weights were also known in Ancient China. [2]
In Islamic civilization, where they are called Sanadjāt, coin weights are said to have been introduced by a Jew named Sumair in 694. [1] Up to that point coins were only compared to coins of good quality. [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. [1]
Coins weights were also known in the Carolingian Empire, where they were stamped with regular coin dyes to clarify their attribution. [3] Islamic coin weights were introduced to Great Britain in the 9-10th century CE through the Vikings. [4]