Liquor iron ore is a rare mineral only found in some countries.
Liquor iron ore has not been seen, but it does have distinguishing features since Koala noticed its presence in stolen weapons. It is very rare, as only some countries are said to have it. It can be used to build tools such as weapons.
Since Doflamingo's main seller was Kaido, who produces his weapons in Wano, the main source of these weapons could be Wano country.