UV light causes mineral and fabric samples to fluoresce different colors.

Mineral and cloth samples fluoresce under UV light. High voltage in the UV lamp accelerates electrons that collide with atoms of gas in the lamp tube. The excited atoms jump down to their normal levels, emitting UV photons. When the UV photons hit the surface of the the mineral and cloth samples, their atoms absorb photons and are excited to higher energy levels. The atoms then return to lower energy levels in a series of two or more jumps, emitting photons that have a frequency in the visible light region, in a process called fluorescence.