Labradorite is a mineral from the group of feldspars. In labradorite, the iridescent (changing) play of colors with a metallic luster is striking. This so-called labradorescence is caused by interference and mirroring on the submicroscopic lamellae. This gloss is mostly blue, purple and green, sometimes there are other colors. In rare cases, the luster covers the entire color spectrum, such a decorative stone is then called spectrolite.