Bubbles in the Bullion: Micro-CT Imaging of the Internal Structure of Ancient Coins

The earliest coins known to mankind were made of electrum, an alloy of gold and silver, in Western Turkey in the middle of the 7th century BCE, within the geographical and political context of the Lydian Empire. The invention of coinage created new economic patterns and behaviours in the ancient world, which remain fundamentally in place today. Such Lydian and other coins are irregularly shaped but approximately circular. Interestingly, they adhere strictly to a set of weight standards and have weights ranging from ~17 g (stater) to ~0.05g (1/192 th stater) Many of the coins have designs on the obverse and more simple punches on the reverse. The coin discussed in this paper (ANS 1977.158.75 ) (Fig.