Alexandrite: The Rare Color-Change Birthstone of June
Often described by gem aficionados as “emerald by day, ruby by night,” alexandrite is the very rare color-change variety of the mineral chrysoberyl. Originally discovered in Russia’s Ural Mountains in the 1830s, it is now found in Sri Lanka, East Africa, and Brazil, but fine material is exceptionally rare and valuable. As one of the three official birthstones for June—alongside pearl and moonstone—alexandrite holds a unique position in the gemological world, celebrated for its remarkable optical phenomenon and deep historical roots. This article will explore the rich history and lore of alexandrite, its geological formation and sources, its precise gemological properties, its enduring symbolism, and practical guidance for its care and maintenance, all based exclusively on verified information from authoritative sources.
History and Lore
The story of alexandrite begins in the Ural Mountains of Russia, where it was first discovered in 1830. The gemstone was initially mistaken for an emerald due to its green hue in daylight. However, its remarkable hardness and its ability to change color under different light sources quickly distinguished it. The stone was named after the future Czar Alexander II, who was known for emancipating Russia’s serfs. This royal association immediately linked the gem to wealth and nobility, cementing its status as a stone of opulence.
The color-change phenomenon of alexandrite was particularly significant in Russian culture. The stone’s ability to shift from a bluish green in daylight to a purplish red in incandescent light mirrored the imperial national colors of old Russia—green and red. This coincidence fueled its legend and made it a symbol of the Russian Empire. While the original Russian deposits in the Ural Mountains are now largely depleted, the legacy of these early discoveries continues to define the gem’s prestige.
Alexandrite’s journey to becoming a modern birthstone is a more recent development. In 1952, the Jewelry Industry Council of America officially designated alexandrite as a birthstone for the month of June. This recognition, which it shares with pearl and moonstone, significantly increased its popularity and demand. Furthermore, alexandrite is also recognized as the gemstone for the 55th wedding anniversary, adding another layer of ceremonial significance to its history.
Geological Formation and Sources
Alexandrite is a variety of the mineral chrysoberyl, with the chemical formula BeAl₂O₄. Its distinctive color change is the result of trace amounts of chromium substituting for aluminum in the crystal lattice. The presence of chromium is what allows the gem to absorb specific wavelengths of light, creating the shift from green to red. This specific chemical composition is relatively uncommon in nature, which is a primary reason for the stone’s rarity.
The formation of alexandrite typically occurs in metamorphic rocks, often alongside other gem materials. Historically, the most significant sources were in Russia’s Ural Mountains. However, as these deposits became exhausted, other localities emerged. Today, fine alexandrite is also mined in Sri Lanka, East Africa (particularly Tanzania), and Brazil. Sri Lankan deposits, for instance, have yielded some of the largest known examples of alexandrite, including a 65.7-carat color-change stone. Brazilian deposits also contribute to the global supply, though high-quality, facetable material from all locations remains exceptionally rare.
It is important to note that alexandrite is often recovered incidentally while mining for other gemstones like emeralds and corundum (rubies and sapphires). This incidental recovery further underscores its scarcity, as dedicated mining operations for alexandrite itself are limited.
Gemological Properties
Alexandrite’s value is intrinsically linked to its unique set of physical and optical properties. These characteristics are what gemologists use to identify and grade the stone.
Color and Color Change The most defining quality of alexandrite is its dramatic color change. Fine alexandrite appears bluish green in daylight or fluorescent light and shifts to a red to purplish red in incandescent light. The intensity and completeness of this change are critical factors in determining its quality and value. A more pronounced and vivid shift commands a higher price. The phenomenon is caused by a specific absorption band at 580nm, which allows the gem to transmit red and green light differently depending on the light source.
Clarity As a naturally occurring gemstone, alexandrite typically contains inclusions. Good quality alexandrite is generally “eye-clean,” meaning inclusions are not visible to the naked eye. However, some stones may have inclusions that are characteristic of their formation. In some cases, alexandrites may undergo treatments like fracture-filling or oiling to improve apparent clarity, though most high-quality natural alexandrites are not treated.
Hardness and Durability With a Mohs hardness of 8.5, alexandrite is an exceptionally durable gemstone, harder than emerald and suitable for all types of jewelry, including rings that are worn daily. This excellent hardness and toughness make it resistant to scratching and abrasion under normal wear.
Refractive Index and Other Properties Alexandrite has a refractive index ranging from 1.746 to 1.755 and a birefringence of 0.008 to 0.010. Its specific gravity is 3.73. These optical properties are used in gemological laboratories to confirm the gem’s identity and distinguish it from synthetic or imitation materials.
Size and Carat Weight While alexandrite can be found in a variety of sizes, gems greater than two carats are considered large in the world of alexandrite. Given the rarity of larger stones, the price-per-carat increases significantly for gems over 1 carat, with further jumps at 2, 5, and 8 carats. The largest known natural alexandrite is a 65.7-carat stone from Sri Lanka. Russian alexandrites have been faceted into gems around 30 carats, but these are exceptionally rare.
Summary of Key Gemological Properties
| Property | Measurement / Description |
|---|---|
| Mineral | Chrysoberyl |
| Chemical Formula | BeAl₂O₄ |
| Color | Bluish green in daylight; purplish red in incandescent light |
| Mohs Hardness | 8.5 |
| Refractive Index | 1.746 to 1.755 |
| Birefringence | 0.008 to 0.010 |
| Specific Gravity | 3.73 |
| Primary Cause of Color | Trace amounts of chromium |
Symbolism and Metaphysical Beliefs
Beyond its scientific attributes, alexandrite is steeped in symbolism and metaphysical lore. Its dual-color nature has long been associated with balance, duality, and the harmony of opposing forces. In Russian tradition, the gem’s ability to display both the imperial green and red colors symbolized the nation’s power and fortune.
Metaphysically, alexandrite is often called a “stone of good omens.” It is believed to bring joy, luck, and intuition to its wearer. Its color change is thought to reflect the wearer’s emotional state, acting as a kind of barometer for inner feelings. Some beliefs hold that alexandrite can help in decision-making by revealing both sides of a situation, much like it reveals both green and red under different lights.
In modern crystal healing practices, alexandrite is associated with the crown chakra and is believed to enhance creativity, inspiration, and spiritual enlightenment. Its rarity and beauty make it a prized possession not only for its aesthetic appeal but also for the personal significance and perceived energy it brings to the individual.
Care and Cleaning
Given its excellent hardness and durability, alexandrite is relatively easy to care for. It is suitable for everyday jewelry and can withstand normal wear and tear. However, like all gemstones, it requires proper maintenance to preserve its beauty.
Cleaning: - Use warm water, mild soap, and a soft brush (like a toothbrush) to clean alexandrite jewelry. - Avoid harsh chemicals, such as bleach or ammonia, which could damage the stone or its setting. - Ultrasonic cleaners are generally safe for alexandrite, but it is always advisable to consult with a professional jeweler if the stone has any fractures or inclusions that could be exacerbated by the vibrations. - Steam cleaning is also acceptable for alexandrite, but caution is needed if the stone is set in a delicate or porous setting.
Storage: - Store alexandrite jewelry separately from other jewelry to prevent scratches, even though its hardness makes it resistant to damage from softer stones. - A soft cloth pouch or a compartmentalized jewelry box is ideal for storage.
Professional Maintenance: - Have alexandrite jewelry inspected by a professional jeweler periodically to ensure the setting is secure and the stone is not damaged. - If the stone has been treated (e.g., fracture-filled), follow specific care instructions provided by the gemologist or jeweler.
Conclusion
Alexandrite stands as a testament to nature’s artistry and rarity. From its historic discovery in the Russian Ural Mountains to its status as a cherished June birthstone and anniversary gem, alexandrite has captivated gem enthusiasts, jewelers, and collectors for nearly two centuries. Its remarkable color-change ability, combined with its excellent hardness and scarcity, makes it one of the most valuable and intriguing gemstones in the world. Whether admired for its scientific wonder, its rich historical lore, or its symbolic meanings, alexandrite continues to be a gemstone of profound beauty and significance, embodying the perfect blend of nature’s mystery and human admiration.