Alexandrite, a captivating and exceptionally rare gemstone, holds a distinguished position as one of June’s three recognized birthstones, alongside pearl and moonstone. Its allure stems from a remarkable optical phenomenon – a distinct color change depending on the light source. Exhibiting a green hue in daylight or fluorescent light and transforming to a red or purplish-red under incandescent light, alexandrite has been romanticized as “emerald by day, ruby by night.” This unique characteristic, coupled with its relative scarcity, makes it a highly prized possession among collectors and a symbol of good fortune and balance.
History and Lore
The story of alexandrite begins in the Ural Mountains of Russia in the 1830s. Its discovery coincided with the reign of the future Tsar Alexander II, then a young crown prince, and the gemstone was promptly named in his honor. The gem’s striking color shift resonated deeply with the Russian aristocracy, mirroring the national military colors of imperial Russia – red and green. This association cemented alexandrite’s popularity within the Russian upper classes, becoming a favored gemstone among the elite.
Beyond its Russian origins, alexandrite has accumulated symbolic meaning across different cultures. Historically, it has been linked to prosperity, good luck, and harmony. The stone’s ability to adapt and change color is often interpreted as a representation of balance and duality, reflecting the complexities of life and emotions. In Russia, alexandrite symbolized royal elegance, further enhancing its prestige.
Geological Formation and Sources
Alexandrite is a variety of the mineral chrysoberyl, composed primarily of beryllium, aluminum, and oxygen. Its color-changing ability is attributed to the presence of chromium within its crystal structure. The formation of alexandrite requires a unique geological environment, involving the presence of both beryllium and chromium, which are rarely found together in nature.
Initially discovered in the Ural Mountains of Russia, these deposits were the primary source of alexandrite for a significant period. However, Russia is no longer a major producer of the gemstone, although smaller quantities are still mined there. Today, alexandrite is found in several locations around the world, including Brazil, Sri Lanka, Madagascar, and Myanmar. Significant sources include Russia, Sri Lanka, and Brazil, though the supply remains limited, contributing to its high value.
Gemological Properties
Alexandrite possesses a unique combination of gemological properties that contribute to its beauty and desirability. It scores an 8.5 on the Mohs hardness scale, making it a durable gemstone suitable for various jewelry applications. Its crystal structure is orthorhombic, and it exhibits a vitreous (glassy) luster.
The most defining characteristic of alexandrite is its pleochroism and color-changing ability. It displays different colors when viewed from different angles, and its color shifts dramatically depending on the light source. In daylight or fluorescent light, it typically appears green, blue-green, or yellowish-green. Under incandescent light, it transforms to red, raspberry red, or purplish-red. The intensity of the color change varies depending on the stone’s quality and the chromium content.
Here's a table summarizing key gemological properties:
| Property | Value |
|---|---|
| Mohs Hardness | 8.5 |
| Chemical Formula | BeAl₂O₄ |
| Crystal Structure | Orthorhombic |
| Luster | Vitreous (glassy) |
| Transparency | Transparent to opaque |
| Refractive Index | 1.745-1.759 |
| Density | 3.68-3.80 |
| Cleavage | Distinct/good to poor on {110} |
| Fracture | Conchoidal or uneven/irregular |
| Streak | White |
| Optical Effects | Color-change, Chatoyancy (rare) |
| Birefringence | 0.008-0.010 |
| Dispersion | 0.015 |
In rare instances, alexandrite can exhibit chatoyancy, also known as the cat’s-eye effect, when long, thin inclusions are oriented parallel to each other within the stone. This phenomenon further enhances its rarity and value.
Symbolism and Metaphysical Beliefs
Throughout history, alexandrite has been associated with various symbolic meanings. It is often considered a stone of good luck, prosperity, and harmony. Its color-changing property is frequently linked to balance and adaptability, reflecting the ability to navigate life’s complexities. The gemstone’s connection to Russian royalty has also imbued it with connotations of elegance and prestige.
Distinguishing Genuine Alexandrite
Identifying genuine alexandrite requires careful observation and, ideally, professional evaluation. The most straightforward method is to check for its characteristic color change. A true alexandrite will appear green or blue-green in sunlight and red, orange-yellow, or magenta under incandescent light. However, synthetic alexandrite and other color-changing gemstones exist, making accurate identification challenging.
For definitive confirmation, it is highly recommended to have the gemstone graded and certified by a reputable gemological laboratory, such as the Gemological Institute of America (GIA) or the American Gem Society (AGS). These laboratories employ advanced testing methods to determine the stone’s authenticity and quality.
Jewelry Applications and Market Value
Due to its rarity, alexandrite is not typically used in industrial applications. Instead, it is primarily valued for its beauty and used in exquisite jewelry pieces. Jewelers often set small, high-quality faceted alexandrite gems into ornate, high-end designs, such as pendants, rings, earrings, and bracelets. Custom alexandrite jewelry is popular for special occasions, including birthstone gifts for those born in June and 55th wedding anniversary celebrations.
The value of alexandrite is significantly influenced by its color change, clarity, cut, and carat weight. Stones exhibiting a vivid green to bluish-green in daylight and an intense red to purplish-red in incandescent light are the most prized. The rarity of high-quality alexandrite contributes to its high market value, making it one of the most expensive gemstones available.
Care and Cleaning
Alexandrite, with a Mohs hardness of 8.5, is a relatively durable gemstone. However, it still requires careful handling and cleaning to maintain its brilliance. It is best to clean alexandrite with warm, soapy water and a soft brush. Avoid ultrasonic and steam cleaners, as they may damage the stone. As with all gemstones, it is advisable to store alexandrite jewelry separately from other pieces to prevent scratching.
Conclusion
Alexandrite stands as a testament to the wonders of nature, a gemstone celebrated for its captivating color change, historical significance, and exceptional rarity. From its origins in the Ural Mountains of Russia to its current status as a coveted birthstone, alexandrite continues to fascinate and inspire. Its unique combination of beauty, durability, and symbolism ensures its enduring appeal for generations to come.