Mobium currency in coins.
Mobiums are objects that appear in the AngieYaz/RoseOfSharon reboot of Sonic Underground. It refers to the global currency used on Mobius. It exists in both coins and banknotes. However, they both don't seem to have any faces on them like, say, currencies from Earth do (with one exception). Mobiums are issued in the form of Royal Reserve Notes, popularly called greenbacks due to their predominantly green color.
History[]
Sonia holding seven Mobiums in banknotes.
It is unknown for how long Mobiums have been in use, and what the exchange rate is between them and, for example, United States dollars or the British pound sterling. The minting facilities look the same as those on Earth, but (like all the building on Mobius) they are made of metals.
For Dr. Robotnik to maintain a source of income for his empire, the wealthy (namely the aristocrats) were generally spared from roboticization. To protect his family from the same, Mr. Edmund Speedington, the father of Amy Rose, disguised his house as a mansion and was periodically given money by Farrell, as he had very little money himself, just to support his family.
The Mobium became an important interplanetary reserve currency after the First Mobian War. The Mobium is the most widely used currency in interplanetary transactions, and a free-floating currency. It is also the official currency in several countries on Mobius and the de facto currency in many others, with Royal Reserve Notes (and, in a few cases, coins) used in circulation.
The Coinage Act[]
During the rule of King Frederick Archibald Hedgehog's great-great-great grandfather, the Patliament of Mobius passed the Coinage Act, of which Section 9 authorized the production of various coins, including:
Mobiums or Units—each to be of the value of a Dream Stone as the same is now current, and to contain three hundred and seventy-one grains and four sixteenth parts of a grain of pure, or four hundred and sixteen grains of standard Mobian silver.
Section 20 of the Act designates the Mobium remaining as the unit of currency of Mobius:
[T]he money of account of Mobius shall be expressed in Mobiums, or units…and that all accounts in the public offices and all proceedings in the courts of Mobius shall be kept and had in conformity to this regulation.