Birthstones have captivated humanity for centuries, embodying a unique fusion of geological wonder, historical significance, and personal meaning. While many gemstones hold sentimental value, a select few command extraordinary prices due to their rarity, beauty, and storied past. Among these, one gemstone consistently stands out for its astonishing value and magical properties: alexandrite. Often surpassing even diamonds in price per carat for exceptional specimens, alexandrite is a marvel of nature, a stone that shifts its hue from emerald green in daylight to ruby red in incandescent light. This article delves into the world of alexandrite, exploring its rich history, unique geological formation, gemological properties, and the factors that contribute to its status as the most expensive birthstone. We will examine its journey from the Ural Mountains of Russia to modern jewelry markets, and provide practical advice for caring for this remarkable gem.
History and Lore
The concept of birthstones, while popularized in its modern form in the 19th century, has ancient roots. The tradition is often traced back to the biblical description of the High Priest Aaron’s breastplate, adorned with twelve stones representing the tribes of Israel. Over centuries, these stones became loosely associated with the months of the year, a practice that gained widespread popularity in Europe and North America by the 19th century. The formalization of birthstone lists is a more recent development. By the 1870s, Tiffany & Co. played a pivotal role in reviving the custom, and in 1912, the American National Retail Jewelers Association (now the Jewelers of America) published an official, modern list. While additions have been made since, the tradition has remained largely unchanged.
Alexandrite’s own history is as dramatic as its color change. Discovered in the Ural Mountains of Russia in 1830, this gemstone was named after Czar Alexander II, then heir to the throne, as its discovery coincided with his birthday. The stone’s red and green hues mirrored the military colors of Russia, leading to its designation as the national stone of the country. Legend and history intertwine here; the gemstone was not merely a mineralogical curiosity but a symbol of national pride. Its initial source, however, was short-lived. The original Russian mines operated for only a few decades before the primary source was depleted, contributing to the stone’s legendary rarity. The closure of these mines meant that fine, newly mined alexandrite became exceedingly scarce, with much of the high-quality material found today residing in vintage jewelry from that era.
Alexandrite is one of June’s birthstones, alongside pearl and moonstone. Its color-changing property, where it appears as an “emerald by day and a ruby by night,” has fueled its lore and desirability for nearly two centuries. This dual nature made it a favorite among Russian aristocracy and later, global collectors, who prized it not only for its beauty but for its unique narrative of imperial grandeur and subsequent scarcity.
Geological Formation and Sources
The genesis of alexandrite is a testament to the extreme conditions required to form some of the world’s most precious gems. As a variety of the mineral chrysoberyl, alexandrite forms under specific geological circumstances that are both rare and geographically constrained. The presence of chromium, the same element that gives emeralds their green color, is essential for alexandrite’s formation. However, in alexandrite, chromium’s effect is modified by the gem’s crystal structure and trace elements, resulting in its famed color change.
The original and most historically significant deposits were located in the Ural Mountains of Russia. These mines, active in the 19th century, produced the finest alexandrite known to the world, characterized by a vivid, saturated color change from bluish-green in daylight to a rich purplish-red in incandescent light. The geological conditions in the Urals were perfect for creating these gems, but the deposits were limited and have since been largely exhausted. The closure of these mines shortly after their discovery cemented the stone’s rarity and drove up its value exponentially.
Modern sources of alexandrite are limited and produce stones of varying quality. Significant deposits have been found in Brazil, particularly in the states of Minas Gerais and Bahia. Brazilian alexandrite often exhibits a different character from the Russian stones, with color changes that may be less dramatic or from green to brownish-red rather than the classic green-to-purplish-red of the Uralian gems. Other minor sources include Sri Lanka, India, and Zimbabwe, but these locations produce alexandrite in much smaller quantities and often with different color characteristics. The scarcity of new, high-quality material means that a significant portion of the market for fine alexandrite is sustained by the vintage stones from the original Russian mines, making it one of the few gemstones where historical provenance can significantly impact value.
Gemological Properties
Alexandrite’s value is deeply rooted in its exceptional and unique gemological properties. Its most famous characteristic is its strong pleochroism and color change, which is caused by the way chromium ions absorb light within the crystal lattice. Under daylight (which has a higher proportion of blue and green wavelengths), the stone appears green to bluish-green. Under incandescent light (which is richer in red and yellow wavelengths), the stone shifts to a red to purplish-red hue. This phenomenon is not a surface effect but an intrinsic property of the mineral, making it a genuine marvel of nature.
The following table summarizes the key gemological properties of alexandrite:
| Property | Description |
|---|---|
| Mineral Species | Chrysoberyl (BeAl₂O₄) |
| Crystal System | Orthorhombic |
| Hardness (Mohs Scale) | 8.5 |
| Refractive Index | 1.746 - 1.755 |
| Specific Gravity | 3.73 |
| Chemical Formula | BeAl₂O₄ (with Cr³⁺ impurities) |
| Luster | Vitreous (glass-like) |
| Transparency | Transparent to translucent |
| Typical Cut | Brilliant, step, or mixed cuts to maximize color change |
Alexandrite’s hardness of 8.5 on the Mohs scale makes it exceptionally durable and resistant to scratching, second only to diamond (10) and moissanite (9.25) among commonly used gemstones. This toughness makes it suitable for all types of jewelry, including rings, which are subject to daily wear. Its refractive index and specific gravity are typical for chrysoberyl, and its chemical stability is high; it is resistant to most chemicals and can be safely cleaned with common methods. The presence of chromium is what gives alexandrite its color, and the concentration of this trace element directly influences the intensity and quality of the color change. Fine alexandrite displays a strong, distinct color change with no gray or brown overtones, a characteristic that is the primary determinant of its value.
Symbolism and Metaphysical Beliefs
Beyond its physical properties, alexandrite is steeped in symbolism and metaphysical lore, which adds to its allure. Historically, its dual-color nature was seen as a symbol of balance. The green hue, associated with the natural world and renewal, and the red hue, linked to passion and energy, were thought to represent the harmony between the physical and spiritual realms. In Russian culture, its colors were directly tied to national identity, embodying the strength and vitality of the empire.
Metaphysically, alexandrite is often called the “stone of change.” It is believed to enhance intuition, promote creativity, and bring good fortune to its wearer. Some traditions hold that it can help one adapt to change and overcome obstacles, a fitting belief for a stone that literally changes its appearance. It is also associated with the crown chakra and is thought to facilitate a connection to higher consciousness and spiritual insight. While these beliefs are not scientifically verifiable, they form a significant part of the gemstone’s cultural identity and are a key reason why it is cherished by collectors and those interested in the spiritual aspects of gemstones. The stone’s rarity and its dramatic color shift naturally lend themselves to metaphors of transformation and duality, themes that have resonated with people across cultures since its discovery.
Care and Cleaning
Given its exceptional hardness and durability, alexandrite is relatively easy to care for, making it an excellent choice for jewelry intended for regular wear. Its 8.5 Mohs hardness means it is highly resistant to scratching from everyday objects like dust, which typically contains quartz (hardness 7). However, like all gemstones, it should be protected from sharp blows and extreme temperature changes, which could potentially cause cleavage or fracturing, though alexandrite has no distinct cleavage, making it quite tough.
For cleaning, alexandrite can be safely cleaned using warm, soapy water and a soft brush. A mild dish soap diluted in lukewarm water is effective for removing oils and dirt. Ultrasonic cleaners are generally safe for alexandrite, as it is resistant to most chemicals and the vibrations are unlikely to damage the stone. However, it is always advisable to check the integrity of the jewelry setting before using an ultrasonic cleaner, as loose stones could be dislodged. Steam cleaners are also safe for alexandrite, but caution should be exercised with any gemstone that has been fracture-filled or treated, though alexandrite is rarely treated. The primary concern for alexandrite jewelry is not the stone itself but the setting. Prong settings should be checked periodically to ensure the stone is secure, as a lost alexandrite is a significant financial loss due to its high value.
Market Value and Rarity
Alexandrite’s position as the most expensive birthstone is a direct result of its extreme rarity and unique properties. While diamonds are valued based on the four Cs (carat, cut, color, and clarity), alexandrite’s value is driven almost exclusively by the quality and strength of its color change. High-quality alexandrite with a vivid, saturated color change from green to red can command prices from $15,000 to over $70,000 per carat, far exceeding the price of most diamonds of comparable size.
The primary factor driving this cost is the severe scarcity of the material. The original Russian mines, which produced the finest specimens, are no longer a source of new material. Modern Brazilian deposits, while productive, yield stones that often do not match the color quality of the Russian gems. Furthermore, large crystals suitable for faceting are rare, and stones over one carat in weight are exceptionally valuable. The market for alexandrite is a niche one, dominated by collectors, connoisseurs, and high-end jewelers. Its value has shown a consistent upward trend over the decades, as the known supply continues to diminish and demand from an affluent global market increases.
When comparing alexandrite to other expensive birthstones like diamond, ruby, and emerald, its price per carat for top-quality material is significantly higher. While a flawless, colorless diamond of 1 carat might cost tens of thousands of dollars, a 1-carat alexandrite with a strong color change can easily surpass that. This is not to say all alexandrite is more expensive than all diamonds; a low-quality alexandrite with a weak color change will be less valuable than a high-quality diamond. However, at the pinnacle of quality, alexandrite reigns supreme in terms of price per carat among birthstones.
Conclusion
Alexandrite stands as a testament to nature’s artistry and the powerful interplay between geology, history, and human desire. Its journey from a chance discovery in the Russian Ural Mountains to its status as the world’s most expensive birthstone is a narrative of rarity, beauty, and cultural significance. The stone’s mesmerizing color change, from green to red, is not merely a visual curiosity but a complex gemological phenomenon that has captivated scientists and gem lovers alike. Coupled with its exceptional durability, alexandrite is both a precious jewel and a resilient one, capable of being worn and cherished for generations.
The historical weight it carries, from its imperial Russian origins to its place on the modern birthstone list for June, adds layers of meaning that transcend its monetary value. For collectors, jewelers, and individuals seeking a gemstone of profound beauty and rarity, alexandrite represents the pinnacle of what the earth can produce. Its care is straightforward, but its acquisition is a significant undertaking, requiring an eye for quality and an appreciation for its unique story. In the world of birthstones, alexandrite is more than a gem; it is a symbol of change, balance, and the enduring allure of the natural world’s most hidden treasures.