Labradorite is a distinctive mineral prized for its remarkable play of color, a phenomenon known as labradorescence. This visually striking gemstone is a member of the feldspar family, the most abundant group of minerals in the Earth’s crust. It is classified as a plagioclase feldspar. The mineral’s usual base color is a modest gray, dark green, or gray-white, which serves as a canvas for its stunning optical effect. Labradorescence is the unique iridescence that flashes across the stone, displaying metallic hues of blue, green, yellow, and sometimes violet. This shimmering spectacle is caused by the diffraction of light reflecting off microscopic, layered mineral structures inside the crystal.
The Geologic Origin and Naming
The formation of labradorite is associated with the cooling and solidification of magma deep within the Earth’s crust. It is a constituent of mafic igneous rocks, such as basalt and gabbro, but it is most concentrated in anorthosite. Anorthosite bodies are uncommon, composed almost entirely of this calcium-enriched feldspar mineral. The slow cooling process allows for the development of the internal, lamellar structures responsible for the stone’s signature labradorescence.
The mineral derives its name from the rugged, northern region where it was first officially identified. Moravian missionaries discovered the stone in 1770 on Paul Island, near the town of Nain in Labrador, Canada. Although local Inuit tribes were already familiar with the stone, the missionaries were the first to document and name the mineral for the geographic region.
Major Global Mining Locations
The bulk of the world’s commercially mined labradorite originates from a few key geographic locations, each producing material with distinct characteristics. The original source, Labrador, Canada, remains an important location. Although not the largest producer today, Canadian deposits produce high-quality material, often featuring vivid blue and gold flashes. This extracted material is used for jewelry and large-scale architectural and ornamental stone applications.
Madagascar has become one of the most significant modern sources, supplying a large volume of the gemstone to the global market. The material is valued for its bright, varied hues, frequently exhibiting purple and pink tones. These deposits yield large pieces utilized for carvings, spheres, and high-quality jewelry.
The Ylämaa region in southeastern Finland is the exclusive source of Spectrolite, a unique and highly prized variety of labradorite. Spectrolite is essentially a high-grade labradorite, distinguished by its exceptionally intense labradorescence that displays the full color spectrum. This variety, with its dark base and vibrant rainbow flash, was discovered accidentally in 1940 by a soldier during World War II. Its superior clarity and broad range of color have established it as a specialty product, often commanding higher prices.
Notable Secondary and Specialty Sources
Beyond the three primary commercial producers, labradorite is extracted from several other locations, typically in smaller volumes or for specialty markets. Deposits in Russia, particularly near the Kola Peninsula, contribute to the global supply, though the consistency and volume may be less than the major sources.
The United States also yields unique varieties, with Oregon being a prominent example. Labradorite found there, often marketed as Oregon Sunstone, can display a metallic glittering effect called aventurescence, caused by minute copper inclusions. This material is often transparent and is cut for jewelry that highlights both the internal sparkle and the stone’s pleochroism.
Other smaller-scale or intermittent sources include Mexico, Australia, and Norway. The material from these secondary sites often features less intense labradorescence or is focused on serving niche collector markets rather than mass commercial production.