Bilbok were black rectangular coins. They were the currency used on the planet Eco. The Ecocid hive mind would provide bilbok for visitors to the planet, in exchange for certain items (such as phasers) that it would then study. (DS9 novel: Antimatter)

Types of currency
materials	acta crystal • gold • latinum • ludugial gold • silver
units	bilbok • cent • credit • darsek • dejebbit • dirak • dollar • drokna • ducat • galorine credit slip • ilec • kern • klon peag • laertian dinar • lek • lita • notch-rock • prime transfer authority • quatloo • sakto • sous • szeket • t'chak • talon • tri-esta