Geological & Scientific Properties | Finland Spectrolite
Finland Spectrolite is a captivating and unique variety of labradorite, a feldspar mineral known for its remarkable play of colors. Spectrolite is specifically known for its rich spectrum of colors and was first discovered in Finland, hence its name. Here's an overview of Finland Spectrolite's geological and scientific properties:
Chemical Composition and Structure:
- Composition: Spectrolite, like labradorite, is a plagioclase feldspar with the chemical composition (Ca,Na)(Al,Si)_4O_8. The presence of calcium and sodium varies within the mineral.
- Crystal System: It crystallizes in the triclinic system, forming in aggregate structures rather than individual crystals.
Physical Properties:
- Color and Labradorescence: While the base color of Spectrolite is typically dark gray to black, its most striking feature is the vivid play of colors or labradorescence. This phenomenon can include a wide spectrum of colors such as blues, greens, oranges, reds, and sometimes purples.
- Hardness: Spectrolite has a hardness of about 6 to 6.5 on the Mohs scale.
- Luster: The luster of Spectrolite is typically vitreous to pearly.
- Transparency: This mineral is generally opaque.
- Cleavage and Fracture: It has two directions of perfect cleavage, typical of plagioclase feldspars, and fractures along these cleavages.
Optical Properties:
- Refractive Index: The refractive index of Spectrolite is approximately 1.56 to 1.57.
- Birefringence: Due to its triclinic crystal structure, Spectrolite exhibits a noticeable birefringence.
Geological Occurrence:
- Formation: Spectrolite is found in igneous rocks, specifically in basaltic and gabbroic masses and anorthosite complexes.
- Associated Minerals: It may be associated with other feldspars and pyroxenes in these igneous environments.
Major Deposits:
- The most significant deposits of Spectrolite are in Finland, particularly in the Ylämaa area. It's where it was first discovered during the 1940s and remains the primary source of this unique variety of labradorite.
Finland Spectrolite is renowned for its exceptional color play, which surpasses that of typical labradorite. This unique characteristic, along with its Finnish origin, makes it a highly prized stone in gem and jewelry markets, as well as among collectors and lapidary artists. The beauty and uniqueness of Spectrolite lie in the way it interacts with light, showcasing a mesmerizing array of colors that change and shift when viewed from different angles.
