Crushed limestone is one of the items used to make pig iron.
Crushed limestone is creamish white in color, similar in shade to limestone. It appears similarly to pigments, being a powder.
Crushed limestone must be crafted on a press.
Crushed limestone is used to make pig iron, which can be used to make iron ingots with less iron ore.
It is also used to craft plaster at a builder's bench.
In the real world, limestone contains calcium carbonate, which is used in the purification of iron from ore by reacting with sulfur, an impurity within iron ore.