1/4 Penning

Norway's smallest medieval silver denomination, the quarter penning occupied the absolute floor of the monetary system during the reigns of Sverre Sigurdsson and his immediate successors — a period of prolonged civil conflict between the Birkebeiner faction and the Bagler pretenders. Coins this light were struck in enormous quantities to pay troops and functionaries, which is precisely why so few survive: they were melted, lost, or simply corroded into nothing.

At 0.03 grams, even minor handling losses render a specimen unweighable by most equipment.