Pearls of Wisdom: The Arts of Islam at the University of Michigan

As glass comes in various colors and levels of opacity, glass weights are found in many different colors and even slightly mottled, like this example. Because coins were not always minted according to standard weight and purity levels, glass weights were used to measure the appropriate sum of money required for a purchase, regardless of the number of actual metal coins. Different sets of weights were used for gold, silver, and copper coins. This glass weight is quite small and thus could have been used to weigh a small amount of currency. Indeed, its brownish color is reminiscent of smaller and cheaper copper coins. When used in conjunction with differently sized glass weights, it would have measured weight more accurately.

Bibliography: Miles 1951a; Morton 1985; Bates 1993; 1981; and Balog 1981.