Alexandrite is a rare and remarkable gemstone, celebrated for its extraordinary color-changing phenomenon. As the primary birthstone for those born on June 8th, it holds a unique place in the world of gemology, blending scientific intrigue with captivating lore. This article explores the multifaceted nature of Alexandrite, from its geological origins and gemological properties to its historical significance and enduring symbolism. We will delve into the factors that make this chameleon-like gem a prized possession for collectors and a meaningful choice for June-born individuals.
History and Lore
The story of Alexandrite is intrinsically linked to imperial Russia. The gem was first discovered in the Ural Mountains in 1830, on the future Tsar Alexander II's 16th birthday. The stone's initial discovery is attributed to Finnish-born mineralogist Nils Gustaf Nordenskiöld, who found the green variety in the emerald mines near the Tokovaya River. The gem's remarkable property of appearing green in daylight and red in candlelight or incandescent light was immediately noted. The stone was named "Alexandrite" in honor of the future Tsar, and its dual-color nature was famously declared "the national color of Imperial Russia," as it mirrored the military colors of the empire—red and green.
This association with Russian royalty cemented Alexandrite's status as a symbol of prestige and fortune. In the late 19th and early 20th centuries, it became a favorite among the Russian aristocracy. Its rarity and unique optical properties made it a status symbol, often set in elaborate jewelry pieces. The gem's lore extends beyond its imperial connections. In Russian folklore, Alexandrite was believed to bring good fortune, joy, and intuition to its wearer. It was also thought to be a stone of balance, capable of harmonizing the physical and spiritual realms.
The gem's journey to becoming a modern birthstone is part of a longer historical tradition. The modern list of birthstones, standardized by the American National Retail Jewelers Association in 1912, includes Alexandrite for June. This list has been updated over time, but Alexandrite remains a cornerstone for the month. Its inclusion reflects the gem's growing recognition in the Western world, particularly after the discovery of new deposits in the early 20th century. While the Russian mines are largely depleted, the legend of the original Alexandrite continues to drive its value and desirability.
Geological Formation and Sources
Alexandrite is a variety of the mineral chrysoberyl. Its formation requires a rare and specific geological environment. Chrysoberyl is a beryllium aluminum oxide (BeAl₂O₄), and the color-changing variety, Alexandrite, requires trace amounts of chromium (Cr³⁺) as a chromophore. The chromium ions substitute for aluminum in the crystal lattice, which is responsible for the gem's unique light absorption properties. The presence of vanadium can also contribute to the color change, but chromium is the primary element.
The formation process is complex. Chromium-rich rocks must be present, and the crystal must form under specific temperature and pressure conditions. The most significant deposits are found in pegmatites and metamorphic rocks. Historically, the Ural Mountains in Russia were the primary source, producing stones with a vivid green-to-red color change. These Russian Alexandrites are considered the benchmark for quality, though they are now extremely rare on the market.
Subsequent discoveries have expanded the geographical sources of Alexandrite. Significant deposits have been found in Brazil, Sri Lanka (Ceylon), and East Africa (Tanzania, Zimbabwe, and Madagascar). Brazilian Alexandrite, particularly from the state of Minas Gerais, often exhibits a more dramatic color change, shifting from blue-green to purple-red. Sri Lankan stones typically have a lighter body color and a less pronounced change, often described as bluish-green to red. African sources, especially from Tanzania, are known for producing larger crystals with a strong color change, though they may have inclusions.
The scarcity of high-quality Alexandrite is a key factor in its value. Natural Alexandrite over one carat is exceptionally rare, and stones with a strong color change and minimal inclusions command premium prices. The gem's formation is a testament to the unique geological conditions required to produce its captivating properties, making each natural Alexandrite a product of a specific and rare event in Earth's history.
Gemological Properties
Alexandrite possesses a unique set of gemological properties that define its character and value. Its most celebrated feature is its pleochroism, specifically the phenomenon of color change, which is a result of its specific light absorption characteristics.
Color and Color Change: The primary color of Alexandrite in daylight or fluorescent light is typically a bluish green, green, or yellowish green. Under incandescent light or candlelight, it shifts to a red, purplish-red, or raspberry red. The quality of the color change is a critical valuation factor. The most prized stones exhibit a distinct and dramatic shift from a vivid green to a rich red. The cause of this change lies in the chromium ions, which absorb light in the yellow and blue parts of the spectrum. Daylight, which is rich in blue and green wavelengths, emphasizes the green component. Incandescent light, which is rich in red and yellow wavelengths, emphasizes the red component.
Hardness and Durability: On the Mohs scale of hardness, Alexandrite rates an 8.5. This makes it a very durable gemstone, suitable for all types of jewelry, including rings and bracelets, which are subject to daily wear. Its hardness is comparable to that of topaz and corundum (ruby and sapphire), ensuring it is resistant to scratching and abrasion. However, like all gemstones, it can be fractured by a sharp blow due to its cleavage properties.
Crystal System and Refractive Index: Alexandrite crystallizes in the orthorhombic system. It has a refractive index ranging from approximately 1.746 to 1.755, with a birefringence of 0.008 to 0.010. These optical properties contribute to its brilliance and fire when properly cut. The specific gravity of Alexandrite is typically between 3.70 and 3.73, which is a useful diagnostic property for gemologists.
Clarity and Inclusions: Natural Alexandrite often contains inclusions. Common inclusions are long, parallel tubes or needles, which are characteristic of the chrysoberyl family. These inclusions, sometimes referred to as "silk," can sometimes be visible to the naked eye. While inclusions can affect clarity, some inclusions are accepted as evidence of natural origin. Eye-clean Alexandrite is rare and highly valued.
Treatment: It is important to note that Alexandrite is rarely treated. The color change is a natural property of the stone. While some synthetic Alexandrite exists (typically created using the Czochralski method), it is distinct from natural material. The gemological community relies on advanced testing to differentiate natural from synthetic stones.
The following table summarizes key gemological properties of natural Alexandrite:
| Property | Description |
|---|---|
| Mineral Species | Chrysoberyl |
| Chemical Formula | BeAl₂O₄ |
| Crystal System | Orthorhombic |
| Hardness (Mohs) | 8.5 |
| Refractive Index | 1.746 – 1.755 |
| Specific Gravity | 3.70 – 3.73 |
| Birefringence | 0.008 – 0.010 |
| Primary Cause of Color Change | Chromium (Cr³⁺) |
Symbolism and Metaphysical Beliefs
Beyond its physical properties, Alexandrite is steeped in symbolism and metaphysical lore, which have evolved over centuries. Its most potent symbol is duality, represented by its color change. This has led to its association with balance, harmony, and the integration of opposites.
In Russian tradition, Alexandrite was seen as a stone of "yesterday and tomorrow," embodying the past and the future. It was believed to bring joy and optimism to its wearer, helping to transform negative energy into positive. Its dual colors were thought to represent the balance between the physical and spiritual worlds, making it a popular talisman for those seeking inner peace and clarity.
Metaphysically, Alexandrite is often linked to the heart chakra. It is believed to promote self-esteem, confidence, and the ability to embrace change. Some modern crystal healing practices suggest that Alexandrite can enhance intuition and creativity, helping individuals to see beyond the obvious and perceive hidden truths. Its association with the month of June and the zodiac sign of Gemini (which spans May 21 to June 20) further reinforces its symbolism of adaptability and duality.
While these beliefs are not scientifically verified, they contribute to the gem's allure and cultural significance. For many, wearing Alexandrite is a personal connection to these ancient and modern interpretations, adding a layer of meaning to the gemstone's intrinsic beauty.
Care and Cleaning
Given its excellent hardness (8.5 on the Mohs scale), Alexandrite is a relatively durable gemstone suitable for everyday wear. However, proper care is essential to maintain its beauty and structural integrity over time.
Cleaning: The safest method for cleaning Alexandrite is with warm water, a mild soap (such as dish soap), and a soft brush. Avoid using harsh chemicals, including household cleaners, as they can damage the stone or its setting. Ultrasonic and steam cleaners are generally not recommended for Alexandrite, especially if the stone has significant inclusions or fractures, as the vibrations and heat could potentially cause damage. After cleaning, rinse the gemstone thoroughly with water and dry it with a soft, lint-free cloth.
Storage and Handling: When not being worn, Alexandrite should be stored separately from other jewelry to prevent scratching. A soft pouch or a compartmentalized jewelry box is ideal. While Alexandrite is resistant to light and heat, it is always wise to avoid exposing any gemstone to extreme temperatures or direct, prolonged sunlight, which could affect some treatments or settings.
Precautions: Despite its hardness, Alexandrite can be chipped or fractured by a sharp impact. It is advisable to remove Alexandrite jewelry during activities that could subject it to physical stress, such as heavy manual work, sports, or gardening. Regular inspection of the setting by a professional jeweler is recommended to ensure the stone remains secure.
Conclusion
Alexandrite stands as a gemstone of unparalleled fascination, merging scientific wonder with deep historical roots. From its imperial Russian origins and legendary color-changing properties to its status as the primary birthstone for June 8th, it continues to captivate gemstone enthusiasts, collectors, and jewelry lovers worldwide. Its remarkable hardness makes it a practical choice for fine jewelry, while its rarity ensures its value and prestige. Whether appreciated for its geological uniqueness, its symbolic balance, or its sheer beauty, Alexandrite remains a testament to the extraordinary artistry of nature. For those born in June, it offers a personal connection to a gemstone that embodies change, joy, and the harmonious balance of light and color.