Roman glass coin weight, 450 - 500 AD. This example has a portrait of an emperor encircled by some lettering that is difficult to distinguish. It is a lovely translucent green glass with a subtle iridescence. It feels very satisfying to the touch. Rare and wonderful. Museum quality.
Coin weights were 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). Glass was a preferable medium for these weights, since they could be made relatively easily and any chips or alterations were immediately visible to the naked eye. The usage of coin weights, especially glass ones, goes back to Ptolemaic and Byzantine times, and continued into Islamic times and even into the Carolingian Empire.
The setting is 14 kt gold, quite a lot of it. The chain is a high end- gold plate rope chain. Length 18"