What is luminescence in mineralogy ?

Luminescence : definition

Luminescence refers to any light emitted by a mineral that is not the result of incandescence. This light is generally weak and can only be seen in the dark.

Fluorescence and phosphorescence are the main mineral luminescence but there are others such as thermoluminescence, a property that certain minerals have of emitting visible light by heating (between 50 ° C and 475 ° C), and triboluminescence, light emission caused by impact, crushing or friction.