Night of the Dead Wiki - LimestoneLimestone is a more or less common resource that is mostly used to produce cement at the Material production table. Limestone is found by mining the grey rocks with yellow spots. These rocks contain Limestone, Boulder and Stone. You should mine these whenever you come across them and there is enough time left for you to so. They are not as rare as the black rocks which contain Copper ore and Iron ore.

where to find Grey rocks with yellow spots
stackable 99x
craftable no
where to craft
category Natural resources