Minerals affected by light exposure

These minerals must be perfectly kept out light by, for example, wrapping in black cloth. To prevent photo-oxidation process, minerals may be kept under deoxidized circumstance.

Photo-oxidation: Parasymplesite => Ferrisymplesite; Symplesite => Ferrisymplesite; Vivianite => Metavivianite
Color fade on light exposure: Bermanite (Darken); Bustamite; Fluorite (Rarely); Ilsemannite (Turn blue); Proustite (Darken); Pyrargyrite (Darken); Tyuyamunite (Turn yellowish green)
Photodissociation (Photolysis, Photodecomposition): Calomel => HgCl₂ + Hg; Chlorargyrite => Ag⁺ + Cl^- (turn dark purple); Realgar => Arsenolite + Orpiment; Sideronatrite => Metasideronatrite (under low humidity)
Phase transition on light exposure: Realgar => Pararealgar