Lurex is a brand name for a type of metallic yarn, but has established itself as the colloquial name.
Originally a metallic yarn made out of real metal, it is by now a yarn with a coat of shiny plastic giving the illusion of a metallic shine. It can be glittery or just shiny - subtle or extremely extravagant. This type of yarn can give the illusion of a thread being woven with Gold and Silver or make any cloth shiny. The color can be chosen freely, there is nearly no limitation.
Despite its look, the yarns are getting more softer to touch and there are even special coating for extreme softness.
Most popular usages are for cocktail dresses and disco suits reflecting the dazzling lights during a party. Shiny clothes have remained popular until today and there is no end to be seen. Why would it? Glitter & Glamour remain as popular as ever.