According to Plutarch, the Spartans had an iron obolus of four chalkoi. The obolus is also a measurement of weight. In ancient Greece it was defined as one sixth of a drachma, or about 0.5 gram. In ancient Rome it was defined as 1/48 of a Roman ounce, or about 0.57 gram, but was never issued as a coin as part of the early republican coinage system. Below the drachm was the dupondius (1/5) to the quartuncia (1/480). In modern Greece it is equivalent to one decigram, or 0.1 gram.
The word "obolos" or "obelos" (plural: oboloi, obeloi) means a long thin metal rod, such as a spit. "Oboloi" came to be used as currency because they represented ingots of copper or bronze, and were traded as such. Sparta chose to retain the use of the cumbersome, impractical "oboloi" rather than coins proper, so as to discourage the pursuit of wealth.
The deceased were buried with an obolus, placed under the tongue or on the eyes of the corpse, in order that, once a dead person's shade reached the underworld of Hades, it would be able to pay Charon for passage across the river Acheron. Those without enough wealth, or whose friends refused to follow proper burial rites, were forced to wander the banks of the Acheron for one hundred years.