Ferrous Ore is a primary source of nickel as well as a source of Platinum Dust, Pulverized Shiny Dust, and Iridium Ore. It can be smelted into Nickel Ingots or macerated into Nickel Dust. It is most commonly found on layers 11-14, and more rarely on layers 15-17.
When Ferrous Ore is run through an Industrial Grinder, it also creates one Tiny Pile of Platinum Dust, or a full Platinum Dust using Mercury Cells; one Platinum Dust can be Centrifuged to produce one Iridium Nugget and a Tiny Pile of Nickel Dust.
Without GregTech enabled, Ferrous Ore can be smelted into a single Ferrous Ingot. Pulverizing Ferrous Ore in a Pulverizer produces two Pulverized Ferrous Dust and has a 5% chance to make Pulverized Shiny Dust and a 2.5% chance to make two Pulverized Shiny Dust. It just has the same Spawnrate as Coal Ore.