Bioferrite

Bioferrite refers to a wide family of biologically produced iron-protein crystals which are naturally produced by much of Oceanyka's fauna, either for defence (as armour plating) or for offense (as claws and fangs). Because iron is hard to work with for biological beings, which don't usually come equipped with a blast furnace, bioferrite is rarer than calcium in terms of biologically useful minerals.

It is possible to forge tools, weapons and armour out of bioferrite, but this process requires a skilled craftsman, and the result, while performing about as well as wrought iron, cannot match modern steel. However, its inherent connection to the land is said to ward off malicious spirits.