Steel Ore is one of the new ores added by the Soul Forest Mod. Steel ore can be found in the overworld together with a few of the other Soul Forest Mod's ores. Steel Ore is a high tier ore and can be mined only with a diamond pickaxe or better. It can usally be found in large veins underneath layer 14 in any overworld biome.
The main purpose of steel ore is the crafting of steel, as steel is one tier higher then diamond. A SteelIngot can be smelted in a furnace, you will then get 1 Steel Ingots.
Once you have crafted Steel Ingots, it can also be crafted into Steel Tools and Steel Armour