[john70t]

Caveman method still works today (missing the post-processing forging part):

https://thekidshouldseethis.com/post/primitive-technology-crafts-an-iron-knife-made-from-bacteria

“The ore was a species of bacteria that lives by oxidizing iron dissolved in ground water. It appears as an orange/yellow cloudy precipitate in creeks and ponds. It’s a very common natural occurrence and can be found on all continents. I collected the diluted ore and poured it into a large, porous ceramic pot I made. The water leaked out, leaving behind the concentrated iron bacteria “mud” like substance. I dried it out until it resembled rusty earth. It took a month to collect the ore for one 2 hour smelt, from a stretch of creek about 20 meters long.”