Limestone is a marketable item, and a raw material. Limestone is used to produce Concrete.
Players can obtain Limestone by:
Limestone production in a company is boosted by 20% if the company is located in a region which contains an Limestone deposit.
Producing 1x Limestone in a company consumes 1 Production Point.
Players can use iron to create Concrete, by owning a Concrete production company.
Producing 1x Concrete in a company consumes 10 Production Points and 10 Limestone.