In my opinion, I think that coal is the most important mineral of all. It keeps us warm during winter and it helps train transport food and other goods that we need.
I think the most important mineral to a country is salt. Salt is needed in the diet for the production of iodine. Salt is also used in preserving food items. Also, many aquatic animals survive in salty water. It is also used for seasoning. Salt is also used these days for cloud seeding to allow easy rainfall in countries with low amount of rain. Salt is also used to kill germs or parasites. But if water is a mineral resource, i say water because life is not possible in any way without water. Hope i helped
