The present invention firstly relates to a security feature for a security or value document. The security feature comprises a zinc sulfide luminophore in the form of particles. The zinc sulfide luminophore has the general chemical formula ZnS: Cux, My, Xz; here, M represents one or more elements from a group comprising the chemical elements Co, In and Ni; X represents one or more elements from a group comprising the halides F, Cl, Br and I; and the following applies: 0 < x < 0.002 and 0 ≤ y < 0.00015 and 0 ≤ z < 0.00050. The particles each have cubic phase portions and hexagonal phase portions. When excited by an electrical field, the zinc sulfide luminophore emits a first radiation in the range of the light spectrum between 580 nm and 780 nm. When excited by heating the luminophore to a temperature between 100°C and 150°C, the zinc sulfide luminophore emits a second radiation in the light spectrum. Furthermore, the invention relates to a security and value document, which may for example be a bank note or a passport, an identity card, a driving licence or a postage stamp. The invention also relates to a method for detecting and/or verifying the security feature according to the invention.