Larvikite

The gemstone larvikite, often called black labradorite or pub stone, is named after Larvik, Norway, a city near the Oslo rift where the rough stone is found. These stunning larvikite beads contain inclusions that provide a similar visual effect to labradorite, creating striking rainbow-colored reflections when light hits them from a particular direction. This phenomenon is called labradorescence (or schiller) and has been compared to the look of gasoline on water, or the shimmer of tropical butterfly wings.