Alexandrite, a captivating and exceptionally rare gemstone, holds a distinguished position as one of the three birthstones for June. Revered for its remarkable ability to shift color under different lighting conditions – appearing emerald green in daylight and ruby red under incandescent light – alexandrite is a gem that continues to fascinate both collectors and jewelry enthusiasts. Its unique properties, coupled with a rich history intertwined with Russian royalty, contribute to its enduring appeal and significant value. This article will delve into the history, geological origins, gemological characteristics, and symbolism of this extraordinary stone.
History and Lore
The story of alexandrite begins in 1834 with its discovery in the Ural Mountains of Russia. Finnish mineralogist Nils Gustaf Nordenskiöld initially misidentified the gem as emerald, but quickly realized its unusual characteristic: a dramatic color change when exposed to different light sources. This discovery coincided with the birthday of Czar Alexander II, to whom the gem was subsequently named in honor. The colors – red and green – were also significant as they represented the colors of the Imperial Russian flag and the royal house, solidifying alexandrite’s status as the national stone of Tsarist Russia.
The initial Russian deposits were eventually exhausted, contributing to the gem’s current rarity. Subsequent discoveries have been made in Brazil, Burma, India, Madagascar, Rhodesia (now Zimbabwe), Sri Lanka, Zambia, and Zimbabwe, but the quality and intensity of the color change in these stones often do not match those of the original Ural Mountain specimens. Alexandrite briefly replaced pearl as the primary June birthstone, a shift driven by a perceived greater abundance, though this proved inaccurate as high-quality alexandrite remains exceptionally scarce.
Geological Formation and Sources
Alexandrite is a variety of the mineral chrysoberyl. Its color-changing ability is a result of its unique chemical composition and the presence of chromium impurities within the crystal structure. The formation of alexandrite requires a specific geological environment – the presence of beryllium, chromium, and aluminum.
Historically, the most significant source of alexandrite was the Ural Mountains in Russia. However, these deposits are now largely depleted. Today, the primary sources include Brazil, Sri Lanka, and East Africa. While these newer deposits yield some fine-quality stones, they often exhibit less distinct color change and muddier hues compared to the 19th-century Russian alexandrites. Larger stones, exceeding five carats, are particularly rare and command exceptionally high prices.
Gemological Properties
Alexandrite possesses a unique combination of gemological properties that contribute to its desirability. It registers 8.5 on the Mohs hardness scale, indicating excellent durability and suitability for everyday wear, even in rings. It exhibits no cleavage, meaning it is less prone to fracturing when struck.
The most defining characteristic of alexandrite is its pleochroism, the ability to exhibit different colors when viewed from different angles. This manifests as a distinct color change depending on the light source. Typically, alexandrite appears blue-green to greenish-blue in daylight or fluorescent light, while shifting to red or reddish-purple under incandescent light. The most prized specimens display a vivid green to bluish-green in daylight and a deep red to purplish hue under incandescent light.
Some alexandrite stones also exhibit chatoyancy, also known as the cat’s-eye effect, caused by parallel inclusions within the gem. This phenomenon creates a shimmering band across the stone’s surface, further enhancing its visual appeal.
The following table summarizes key gemological properties:
| Property | Value |
|---|---|
| Hardness (Mohs) | 8.5 |
| Cleavage | None |
| Optical Phenomenon | Color Change, Chatoyancy |
| Chemical Formula | BeAl₂O₄ (with Cr) |
| Specific Gravity | 3.71 - 3.85 |
Symbolism and Metaphysical Beliefs
Throughout history, gemstones have been imbued with symbolic meanings and metaphysical properties. While specific beliefs surrounding alexandrite are less extensively documented than those of some other birthstones, its color-changing nature has led to associations with balance, transformation, and good fortune. The shifting colors are often likened to the complexities of love, presenting different facets depending on the perspective.
Pearls, another June birthstone, symbolize purity and loyalty, and are believed to bring peace, balance, and protection. They are unique in that they are not mined from the earth, but are formed within living creatures. The formation process, involving an irritant being coated with nacre, is often seen as a metaphor for overcoming adversity and finding beauty in imperfection.
Care and Cleaning
Due to its hardness and toughness, alexandrite is a relatively durable gemstone suitable for all types of jewelry. However, proper care is essential to maintain its brilliance and protect its unique color-changing properties. Cleaning can be performed with warm, soapy water and a soft brush. Ultrasonic and steam cleaners are generally considered safe, but caution is advised. Avoid harsh chemicals and abrasive materials, as these can damage the stone’s surface. Regular cleaning will help to preserve the gem’s luster and ensure its continued beauty for generations.
Conclusion
Alexandrite stands as a testament to the wonders of the natural world, a gemstone celebrated for its captivating color change, rich history, and exceptional rarity. From its discovery in the Ural Mountains and association with Russian royalty to its current status as a highly sought-after June birthstone, alexandrite continues to inspire awe and admiration. Its unique combination of beauty, durability, and symbolic meaning ensures its enduring appeal for gemstone enthusiasts, jewelry collectors, and those seeking a truly exceptional and meaningful gem.