Aurum is a currency used in-game to buy Cosmetics, speeding upgrades in Personal Quarters or in Printing and when insuring your Gear, preparing to drop down to Fortuna III. It can be acquired by generating it in your Personal Quarters with the Aurum Generator or you can buy it directly from the shop, in exchange for real money.
The Aurum Generator produces 10 Aurum per day at level 1 and increases to a maximum of 32 Aurum per day at max level.