Terbium (Tb) is a chemical element represented by the symbol 🔬🟦. It belongs to the lanthanide series of elements and is known for its distinctive blue color. Terbium is commonly used in the production of phosphors, which are essential components in fluorescent lamps and television screens. Its unique optical properties make it useful in various applications, including lasers, magneto-optical devices, and as a dopant in solid-state materials.