Labradorite's Worth, Cost, and Data Regarding Jewelry
Unveiling the Schiller Effect in Labradorite
Labradorite, a commonly encountered feldspar, is renowned for its unique optical phenomenon known as the Schiller effect. This captivating display of iridescent colors, reminiscent of peacock feathers, can feature hues ranging from blue and green to gold, yellow, and purple[1].
At the heart of this spectacle lies labradorescence, a multicolored schiller effect distinct from similar phenomena like adularescence seen in moonstone. This mesmerizing effect is caused by thin internal lamellar (layered) structures within the mineral's composition, which result in interference and diffraction of light[1][2].
The Schiller colors in Labradorite vary widely, with bright blues and greens often accompanied by gold and purple hues. This range is broader than in similar feldspar minerals such as peristerite, which exhibits a narrower color range in Schiller[1]. The cause of this vibrant display lies in the internal structure of Labradorite, particularly thin lamellar layers formed by exsolution within the crystal. Sometimes, impurities like copper and lead also contribute to unusual Schiller colors, such as pink, red-orange, or greenish tones[1].
Labradorite displaying Schiller is translucent to opaque and has a hardness suitable for jewelry, comparable to moonstone and other feldspars. It generally shows cleavage that requires care when cutting[1].
Notably, Labradorite with Schiller is found in Oregon and is used in faceted gemstones, typically ranging from 2 to 10 carats. Besides jewelry, polished labradorite-containing rocks are used in building materials due to their ability to showcase the Schiller under different light angles[1].
Intriguingly, Labradorite was named for its occurrence in Labrador. Facetable crystals can be found in Modoc County, California, and Clear Lake, Millard County, Utah. Translucent to opaque labradorite with Schiller colors (blue, green, golden) is widely cut by hobbyists[1].
Hematite inclusions in Madagascar labradorite create an aventurescence or sparkly effect. Sunstone, characterized by a rolling sheen of golden red spangles, is also found in Madagascar[1].
Labradorite in Oregon has specific properties, including refractive indices a = 1.559-1.563; γ = 1.569-1.573; birefringence 0.008; S.G. 2.71-2.73; material is Ab.An[1]. Large sizes of labradorite are available, suitable for facings of office buildings. The best material for cabochons comes from Finland, but it is not common and is fairly expensive[1].
Fine Schiller and very intense labradorite can be found in Finland, where it is called spectrolite[1]. Labradorite with Schiller is also a component of dark-colored igneous rocks used in building and construction. Zircon, magnetite, ilmenite, and rutile tablets are found in Madagascar[1].
In summary, the Schiller effect in Labradorite is an iridescent optical effect caused by internal layered structures, creating a vivid color play, particularly blue and green hues, making Labradorite distinctive and valued both as a gemstone and decorative stone[1][2].
[1] Geology.com. (n.d.). Labradorite. Retrieved May 20, 2023, from https://www.geology.com/rocks/labradorite.shtml
[2] Minerals.net. (n.d.). Labradorite. Retrieved May 20, 2023, from https://www.minerals.net/mineral/labradorite.aspx
The Schiller effect in Labradorite, with its iridescent colors, adds an exotic touch to lifestyle, fashion-and-beauty products, such as jewelry and gemstones crafted from this mineral. Moreover, its use extends beyond personal adornment, as home-and-garden decorative stones can also showcase its striking color play, particularly when exposed to different light angles.
