Isotopes

Isotopes are a rare kind of mineral. Your miners will begin to mine isotopes at around 20 to 30 kilometers depth.

While isotopes can be sold in the Sell Center for money, it's highly recommended not to do it, since you need them for many Blueprints and for Gem Forge, and much more once you reach the reactor, and there is no other source of isotopes than mining. In a nutshell, don't sell isotopes.

Earth[]

Uranium[]

Uranium is the most common isotope. It will start occur at level 24.

Uranium 1: $100 / unit

Uranium 2: $2,000 / unit

Uranium 3: $50,000 / unit

Plutonium[]

Plutonium will start occur at level 34 and achieve maximum at 54 (upgrades and miners still increase the amount you get, but not depth)..

Plutonium 1: $1,000 / unit

Plutonium 2: $20,000 / unit

Plutonium 3: $500,000 / unit

Polonium[]

Polonium is the rarest Earth isotope. It will start occur at level 55 and achieve maximum at 84 (upgrades and miners still increase the amount you get, but not depth).

Polonium 1: $5,000 / unit