A vendril coin is worth 10 gold coins.
A mithril coin is worth 50 gold coins.
A rugauril coin is worth 100 gold coins.
The impressions made on common coinage and their specific naming varies from kingdom to kingdom in the empire. In the Storm Marches kingdom, a gold coin is called a 'Truiga, after the image of the Dowager Queen, Iarel Coatruiga, on the coin's face. The silver coin is a Beck, and the copper coin is a Palter.
The noble metal coins all bear the image of the Imperial Tintajjilat seal. The rugauril coin also bears the image of the First Emperor, Arie'Tsai, and is so-named, though informally, it's called the Arie. The mithril coin bears the image of the Imperial Kinooruen throne, and hence is called a Throne. The vendril coin, the Emperor, bears the image of the reigning emperor.
Out-realm coin is also made from these six metals, and the legality of trading in the the noble metals varies from realm to realm. For example, the Dwarven lands north and west of the Empire allow free trade in all coinage. Many ancient coins found in treasure hoards and ruins also bear out-realm or pre-Imperial markings. Though some less-scrupulous merchants will accept such coin, the adventurer may find himself faced with a sack of gold coin which no merchant will take. Fortunately, there are means by which such coin can be exchanged for coin of the realm. These run the full range of exchanging coin at an Office of the Imperial Exchange to fencing the coin through the local Thieves' Guild. Either extreme will commonly cost the adventurer a 10% to 50% "commission" on the exchange. For some ancient coin, the adventurer may find a better bargain from a dealer in antiquities.