Densinium is an unusually black metal that phosphoresces in dim light. The easiest way to identify this metal is its extremely high density: 39.18 g/cm3. Densinium forms from the decay of a lutetium isotope; this isotope has a half-life of 13 billion years, meaning that densinium is absurdly rare. Extremely resistant to chemical and physical stress, you will often see this material used in weapons, armor, and high-end technology.
Densinium (Geology tree).