There are a few different currencies in Idle Miner Tycoon.
Cash
The money you collect / use in the 5 mines on the Start Continent (Grass).
Idle Cash
The amount of money you earn in a second while the game is closed on the first island (Start Continent).
Super Cash
You get this currency from leveling up your mine shafts & elevator & warehouse , from the Daily Reward, from your Expeditions, Prestige, Event Mines, and for real money in the in-game shop. You can use it to buy Chests, Research Points (Skill Points), boosts from the shop to progress even faster, or to speed up things across the whole Idle Miner world (e.g. unlocking Rock Barriers).
Ice Cash
The money you collect / use in the 5 mines on the Ice Continent.
Idle Ice Cash
The amount of money you earn in a second while the game is closed on the second island (Ice Continent).
Fire Cash
The money you collect / use in the 5 mines on the Fire Continent.
Idle Fire Cash
The amount of money you earn in a second while the game is closed on the third island (Fire Continent).
Dawn Cash
The money you collect / use in the 5 mines on the Dawn Continent.
Idle Dawn Cash
The amount of money you earn in a second while the game is closed on the fourth island (Dawn Continent).
Dusk Cash
The money you collect / use in the 5 mines on the Dusk Continent.
Idle Dusk Cash
The amount of money you earn in a second while the game is closed on the fifth island (Dusk Continent).
Ancient Cash
The money you collect / use in the 5 mines on the Ancient Continent.
Idle Ancient Cash
The amount of money you earn in a second while the game is closed on the sixth island (Ancient Continent).
Shards
The money you collect on the Mainland Mines.
Idle Shards
The amount of money you earn in a second while the game is closed on the Mainland Mines.
Event Cash
The money you collect on the current Event Mine.
e.g. Autumn Mine = Autumn Cash, Candy Mine = Candy Cash
Idle Event Cash
The amount of money you earn in a second while the game is closed on the current Event Mine.
Impossible Cash
The money you collect on the Impossible Island.
Idle Impossible Cash
The amount of money you earn in a second while the game is closed on the Impossible Island.
Frontier Cash
The money you collect on the Frontier Mines.
Idle Frontier Cash
The amount of money you earn in a second while the game is closed on the Frontier Mines.
Frontier Credits
You can collect these by reaching specific milestone in the Frontier Mines. Can be used only in the Frontier Mines. When the event ends, the Frontier Credits will not carry over to the new Frontier Mine events, instead each 600 Frontier Credits will be exchange for 1 Mystery Boost Ticket when the event ends.