Ferrocolumbite

Ferrocolumbite is a mineral belonging to the columbite-tantalite group, which are solid solution series of iron and manganese niobates and tantalates. Specifically, ferrocolumbite is an iron-rich endmember with the chemical formula FeNb2O6, where niobium (Nb) is the dominant element over tantalum (Ta). It forms a complete solid solution with ferrotantalite (FeTa2O6). Ferrocolumbite typically occurs as prismatic crystals, often with striations along the prism faces. Its color ranges from black to dark brown. The mineral is opaque and has a metallic to submetallic luster. It possesses a relatively high specific gravity and a hardness of 6 to 7 on the Mohs scale.

This mineral is found in a variety of geological environments, including granitic pegmatites, alluvial deposits, and metamorphic rocks. It is a source mineral for niobium, also known as columbium. Niobium has numerous industrial applications, including the production of high-strength low-alloy steels, superconducting magnets, and specialized alloys used in aerospace and electronics. Ferrocolumbite is often found in association with other niobium and tantalum minerals, as well as economically important minerals like cassiterite and wolframite. While not as abundant as some other ore minerals, deposits containing ferrocolumbite are economically significant for niobium extraction.