Brannerite

Brannerite is a black to brownish-black uranium and thorium titanate mineral with the chemical formula (U,Ca,Th)(Ti,Nb,Fe)2O6. It is an important ore of uranium, particularly in Australia and Canada. Brannerite typically occurs as small, euhedral to subhedral crystals, often found in placer deposits and pegmatites. It can also be found in hydrothermal veins and disseminated within felsic to alkaline igneous rocks. The mineral is characterized by its high refractive index and strong dispersion. Due to its radioactivity, brannerite is often altered and metamictized, meaning its crystal structure has been damaged by radiation. This alteration can lead to a dull luster and a more amorphous appearance. Despite its metamictic nature, brannerite remains a significant source of rare earth elements in addition to uranium and thorium. Its geological occurrence and properties make it a subject of interest for economic geologists and mineralogists studying uranium deposits and radioactive minerals.