Crystals are the main resouces used to build electronic circuits for computers and other electronic circuits and form certain alloy compounds for shields. Compared to the metal production process, the processing of raw crystalline structures into industrail crystals requires special processing. As such, more energy is required to process the raw crystal than needed for metal. Development of ships and buildings, and specialized research upgrades, require a certain quantity of crystals.
At level 4 there will be a second robot.