Labradorite (a variety of Feldspar)

Hardness: 6-6.5 on Mohs scale. Color: Typically gray to grayish-black, but displays a schiller effect (labradorescence) with iridescent flashes of blue, green, yellow, orange, and red when light hits it at certain angles. Luster: Vitreous to pearly. Crystal Structure: Triclinic. Cleavage: Two distinct cleavages at nearly right angles. Specific Gravity: 2.68-2.72.

Labradorite forms in mafic igneous rocks such as basalt, gabbro, and anorthosite through the crystallization of magma. It is a primary mineral in these rocks. It also occurs in some metamorphic rocks and as detrital grains in sedimentary rocks. Geological Age: Varies depending on the host rock, but it is typically found in older igneous and metamorphic formations.

Industry/Construction: Labradorite's durability and attractive appearance make it suitable for countertops, flooring, and architectural cladding. Jewelry: Highly prized as a gemstone due to its unique labradorescence; often cut into cabochons, beads, and carved pieces. Collecting: Valued by mineral collectors for its optical effects.

The captivating iridescent play of colors in labradorite is known as labradorescence, a phenomenon caused by light diffraction within microscopic lamellar intergrowths of various feldspar compositions. It was first discovered in 1770 by Moravian missionaries on the Isle of Paul in Labrador, Canada, from which it gets its name. Folklore suggests it is a stone of magic, offering protection and enhancing spiritual awareness.

In the field, labradorite is identified by its characteristic dark gray appearance with intermittent flashes of vibrant colors when tilted. It is commonly found in large anorthosite intrusions and mafic igneous rocks. Major deposits are found in Labrador (Canada), Finland, Norway, Madagascar, Russia, and the USA (Oregon, New York). Collectors look for specimens with strong, multi-colored labradorescence and good transparency. Its relatively high hardness helps differentiate it from softer minerals.