Labradorite is a feldspar mineral known for its stunning iridescence, called labradorescence, which flashes colors like blue, green, gold, and purple as light hits internal twinning surfaces, creating a "fire" within the stone. Named for its discovery in Labrador, Canada, it's a popular gemstone, often cut into cabochons to showcase its color play, though it requires careful handling due to its hardness of 6 to 6.5 on the Mohs scale.