Labradorite, a member of the feldspar mineral family, is famous for its striking visual characteristics that make its color a complex subject. The stone’s appearance is not defined by a single static hue but by a dynamic interaction with light. This unique characteristic results in a color that is constantly changing and depends heavily on the angle of observation. The true nature of labradorite’s color involves both a muted base tone and a spectacular internal light show.
The Primary Appearance of Labradorite
The color of labradorite, when viewed under normal conditions or from an angle that does not activate its optical effect, is typically subdued and dark. This static body color usually ranges from a smoky gray to a deep gray-blue, or even near-black in some specimens. The stone is generally translucent to opaque, meaning light struggles to pass entirely through its mass. This muted, somber appearance serves as a stark background that enhances the stone’s hidden brilliance, contrasting sharply with the intense color display that emerges when the stone is turned.
The Optical Phenomenon of Labradorescence
The true answer to the question of labradorite’s color lies in a unique optical effect known as labradorescence. This phenomenon is a type of schiller effect, which produces a metallic, flashing play of color across the stone’s surface. The effect is not caused by pigments within the stone but by the way light interacts with its internal structure.
Labradorescence occurs because the stone contains microscopic, plate-like inclusions called exsolution lamellae, which are thin layers of different feldspar compositions. These internal layers, which are only tens to hundreds of nanometers thick, act like a natural diffraction grating. When light enters the stone, it strikes these layers and is split, reflected, and interfered with, producing a brilliant flash of color.
The specific color observed depends on the thickness and spacing of these layers, as well as the angle at which the light hits the stone. The most common and vibrant hues seen are electric blue and green, which result from thinner internal layers. However, the light flash can also produce gold, yellow, and copper tones. Rarer and more highly valued colors include orange, red, and violet or purple.
The light display is highly directional, meaning the vivid color only appears when the stone is moved or the viewing angle changes. This dynamic, intermittent color flash is why the stone is often described as having an internal “fire” or “glow.”
Notable Varieties and Global Sources
The intensity and range of labradorescence can vary significantly, leading to distinct varieties of the stone. The most highly prized variety is Spectrolite, a trade name given to a high-quality labradorite found exclusively in Finland. Spectrolite is distinguished by its ability to display the full spectrum of colors, including the more uncommon reds, oranges, and purples, often against a particularly dark, opaque base.
In contrast, standard labradorite often displays a more limited range, typically focusing on blue and green flashes. The original discovery site, which gives the stone its name, is Labrador, Canada, where it was found in the late 18th century. Other significant global sources of gem-quality labradorite include Madagascar, which is known for colorful, premium material, and Russia. Additional deposits are found in India and Norway.