Alexandrite, a captivating gemstone celebrated for its remarkable color-changing properties, holds the distinction of being among the most valuable and sought-after birthstones. Associated with the month of June, alongside pearl and moonstone, this rare variety of the mineral chrysoberyl commands exceptional prices, often exceeding even those of diamonds. This article delves into the history, geological origins, gemological properties, and enduring appeal of alexandrite, drawing upon available knowledge to illuminate the characteristics of this extraordinary gem.
A History Rooted in Russian Royalty
The story of alexandrite begins in the Ural Mountains of Russia in 1830. Its discovery is intertwined with a significant historical event: the birthday of Czar Alexander II, then heir to the throne. The gemstone’s unique ability to shift color – appearing bluish-green in daylight and purplish-red under incandescent light – was considered particularly fitting, as these hues mirrored the colors of the Russian military. Consequently, alexandrite quickly became the national stone of Russia, cementing its place in the nation’s history and culture.
The initial Russian deposits were remarkably rich, providing a substantial supply of this newly discovered gem for several decades. However, these sources were eventually exhausted, contributing to its increasing rarity and value. Today, alexandrite remains exceptionally scarce, with limited production from locations outside of its original Russian origins.
Geological Formation and Sources
Alexandrite is a variety of chrysoberyl, a beryllium aluminum oxide mineral. Its color-changing ability is attributed to the presence of chromium impurities within its crystal structure. The formation of alexandrite requires a unique geological environment – specifically, the presence of beryllium, aluminum, chromium, and oxygen in pegmatitic rocks. These rocks, formed during the late stages of magma crystallization, provide the necessary chemical components and conditions for alexandrite to develop.
While the Ural Mountains in Russia were the original and most historically significant source of alexandrite, other locations have yielded smaller quantities of the gem. These include Brazil, Sri Lanka, India, and East Africa. However, the alexandrite from these sources often exhibits less pronounced color change and may contain more inclusions than the prized Russian material. The limited availability from these sources further contributes to the gem’s high value.
Gemological Properties: A Study in Dichroism
Alexandrite’s allure stems not only from its history but also from its exceptional gemological properties. It boasts a hardness of 8.5 on the Mohs scale, making it a remarkably durable gemstone suitable for everyday wear. This hardness is second only to diamond and corundum (ruby and sapphire), ensuring its resistance to scratching and abrasion.
The most defining characteristic of alexandrite is its strong pleochroism, which manifests as a dramatic color change depending on the light source. This phenomenon occurs because the gem absorbs different wavelengths of light depending on the viewing angle and the type of illumination. In daylight or fluorescent light, alexandrite typically appears bluish-green, while under incandescent light (such as a traditional light bulb), it shifts to a purplish-red hue. The clarity of alexandrite can vary, with some stones exhibiting noticeable inclusions. However, these inclusions do not necessarily detract from the gem’s value, particularly if they do not significantly impede its brilliance or color change.
The following table summarizes key gemological properties:
| Property | Value |
|---|---|
| Chemical Formula | BeAl₂O₄ |
| Hardness (Mohs) | 8.5 |
| Refractive Index | 1.743 – 1.753 |
| Specific Gravity | 3.71 – 3.85 |
| Crystal System | Orthorhombic |
| Pleochroism | Strong |
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 associated with some other birthstones, its rarity and unique characteristics have contributed to its perceived powers.
Alexandrite is often associated with good luck, fortune, and balance. Some believe it can promote intuition, creativity, and self-confidence. Its color-changing ability is also seen as a metaphor for adaptability and transformation. Historically, alexandrite was thought to bring protection and vitality to its wearer, aligning with the general beliefs surrounding gemstones and their healing properties.
Value and Market Considerations
Alexandrite consistently ranks among the most expensive birthstones, with prices ranging from $15,000 to $70,000 per carat, and even higher for exceptional specimens. This high value is driven by its extreme rarity, combined with its unique optical properties and historical significance.
Several factors influence the price of alexandrite. The strength and clarity of the color change are paramount, with stones exhibiting a distinct and dramatic shift commanding the highest prices. The size of the gem also plays a crucial role, as larger alexandrites are exceedingly rare. Clarity, cut, and origin also contribute to the overall value. Russian alexandrite, due to its historical importance and superior color change, typically fetches a premium compared to material from other sources.
Compared to other birthstones, alexandrite occupies the highest price bracket, surpassing even diamonds, rubies, and emeralds in per-carat cost. This positions it as a gemstone reserved for discerning collectors and those seeking a truly exceptional and valuable piece of jewelry.
Care and Cleaning
Due to its considerable hardness, alexandrite is relatively durable and can withstand normal wear. However, like all gemstones, it requires proper care to maintain its brilliance and beauty. Avoid exposing alexandrite to harsh chemicals, ultrasonic cleaners, or extreme temperature fluctuations.
Cleaning can be performed using warm, soapy water and a soft brush. Gently scrub the gem to remove any dirt or grime, then rinse thoroughly and dry with a soft cloth. Regular cleaning will help preserve its luster and ensure its continued beauty for generations.
Conclusion
Alexandrite stands as a testament to the wonders of nature and the enduring allure of rare and beautiful gemstones. Its captivating color-changing ability, coupled with its rich history and exceptional durability, has cemented its position as one of the most prized and expensive birthstones. Associated with the month of June, alexandrite continues to captivate gem enthusiasts, jewelry collectors, and those seeking a gemstone that embodies both beauty and rarity. Its unique properties and historical significance ensure that alexandrite will remain a treasured gem for years to come.