What is Alexandrite: Rare Color-Changing Gemstone

Alexandrite stands as one of nature’s most fascinating treasures – a gemstone that appears to transform before your very eyes depending on the light source. Often described as “emerald by day, ruby by night,” this remarkable stone has captivated gem enthusiasts since its discovery in the 19th century. Its rarity in nature, combined with its mesmerizing color-changing properties, has earned alexandrite a place among the most valuable colored gemstones in the world. Whether you’re considering it for a special piece of jewelry or simply curious about this natural wonder, understanding alexandrite’s unique characteristics will help you appreciate what makes this gemstone truly extraordinary.

What is Alexandrite?

Alexandrite is a rare variety of chrysoberyl that exhibits dramatic color change depending on lighting conditions. Under daylight or fluorescent lighting, it typically displays greenish-blue hues, while under incandescent light, it shifts to purplish-red tones. This remarkable color-changing property, known as the “alexandrite effect,” is caused by the unique way the gemstone absorbs light wavelengths due to the presence of chromium in its crystal structure. First discovered in Russia’s Ural Mountains in 1830, alexandrite was named after the future Tsar Alexander II and quickly became prized by Russian aristocracy.

• Alexandrite is a variety of chrysoberyl (chemical formula BeAl₂O₄) with chromium traces that create its color-changing properties, distinguishing it from other chrysoberyl varieties like cymophane (cat’s eye) and ordinary yellow-green chrysoberyl.
• The most valuable alexandrite specimens show a complete shift from emerald green in daylight to ruby red in incandescent light, with the strength and completeness of this color change being the primary factor in determining its value.
• With a hardness of 8.5 on the Mohs scale, alexandrite is exceeded in hardness only by diamonds, moissanite, and corundum (rubies and sapphires), making it highly resistant to scratches and suitable for everyday jewelry wear.
• Natural alexandrite typically forms in small crystals, which is why stones over one carat are extremely rare and command exponentially higher prices than smaller specimens of similar quality.
• While most fine gemstones are valued primarily for color saturation and clarity, alexandrite is judged mainly on the strength of its color change, with stones showing a complete transformation from green to red being the most prized.

Alexandrite’s physical properties make it not only beautiful but also practical for jewelry purposes. Its exceptional hardness means it resists scratching, while its lack of cleavage (the tendency to split along certain planes) makes it resistant to breaking during normal wear. The stone’s refractive properties also contribute to its brilliance when properly cut, allowing it to display excellent luster alongside its fascinating color transitions.

The Discovery of Alexandrite

The discovery of alexandrite represents one of gemology’s most romantic stories, tied closely to Russian imperial history. In April 1834, miners working in the emerald mines near the Tokovaya River in Russia’s Ural Mountains discovered an unusual green stone. According to legend, the stone was found on the very day of future Tsar Alexander II’s coming-of-age ceremony, leading Finnish mineralogist Nils Gustaf Nordenskiöld to name it “alexandrite” in his honor. The coincidence that the stone displayed the imperial Russian military colors of red and green only heightened its association with Russian nationalism.

• The original Russian alexandrite from the Ural Mountains remains the quality standard against which all other alexandrite is measured, with these historical specimens displaying the most dramatic color change from a vivid green to raspberry red and often having exceptional clarity.
• After the depletion of Russian mines in the early 20th century, alexandrite became incredibly rare until new deposits were discovered in Brazil in the 1980s, though Brazilian stones typically show less dramatic color change than their Russian counterparts.
• Other significant alexandrite deposits have been found in Sri Lanka, East Africa (particularly Tanzania and Madagascar), India, and Myanmar, each producing stones with slightly different color characteristics based on their geological formation.
• Alexandrite gained popularity during the Victorian era when the Russian court’s fascination with the gemstone influenced European fashion trends, leading to its incorporation in elaborate jewelry designs.
• Tiffany & Co.’s gemologist George Frederick Kunz played a significant role in popularizing alexandrite in America in the late 19th century, acquiring and promoting exceptional specimens from the Russian imperial mines.

The historical significance of alexandrite extends beyond its Russian origins, as each new deposit discovered worldwide has contributed to the gemstone’s evolving legacy. While the original Russian mines are now largely depleted, the romance surrounding the “emerald by day, ruby by night” continues to captivate collectors and jewelry enthusiasts, making it one of the most sought-after colored gemstones despite its relative newcomer status compared to ancient gems like diamonds, emeralds, and sapphires.

How Alexandrite Changes Color in Different Light

The most fascinating and valuable characteristic of alexandrite is undoubtedly its ability to change color. This phenomenon, officially known as pleochroism, is so distinctively dramatic in alexandrite that gemologists refer to it specifically as the “alexandrite effect.” The color change occurs because of the way chromium ions in the crystal structure absorb light at different wavelengths. This unique interaction with light creates one of the most remarkable visual transformations in the natural world, shifting between green and red hues depending on the viewing environment.

• The color change in alexandrite occurs because chromium ions in the crystal absorb yellow and blue light differently depending on the light source, allowing green wavelengths to dominate in daylight and red wavelengths to dominate in incandescent light.
• The ideal alexandrite displays a vivid bluish-green in daylight or fluorescent light and transforms to a purplish-red in incandescent light, with the most valuable specimens showing a complete and dramatic transformation between these two colors.
• Quality of color change is described in percentages, with top-quality stones showing 100% color change, meaning every part of the stone shifts color completely, while lower-quality stones might show only partial transformation or less dramatic color shifts.
• Lighting conditions significantly impact how alexandrite appears, with natural daylight, fluorescent lighting, LED lighting, and incandescent lighting all potentially showing different color aspects of the stone.
• While alexandrite is the most famous color-change gemstone, other stones like color-change sapphire, color-change garnet, and color-change diaspore can exhibit similar properties but typically with less dramatic effects.
• The alexandrite effect can be enhanced by proper cutting techniques that maximize light interaction with the crystal structure, which is why precision cutting is particularly important for this gemstone.

The color-changing property of alexandrite makes it particularly versatile for jewelry, as it can complement different outfits and settings depending on the lighting environment. This chameleon-like quality has contributed significantly to alexandrite’s mystique and appeal among gemstone collectors. While photographs often struggle to capture the true transformation, experiencing a fine alexandrite’s color change in person reveals why this gemstone commands such high prices and admiration.

Alexandrite Physical Properties

Beyond its famous color-changing ability, alexandrite possesses impressive physical characteristics that contribute to both its beauty and durability. As a variety of chrysoberyl, it inherits exceptional hardness and toughness that make it suitable for all jewelry applications, including rings that endure daily wear. Understanding these physical properties helps explain why alexandrite has become such a prized gemstone despite its relatively recent discovery compared to ancient gems like diamonds and rubies.

• Alexandrite ranks 8.5 on the Mohs hardness scale, making it the third hardest gemstone commonly used in jewelry after diamonds (10) and corundum (9), which allows it to maintain its polish and resist scratching even with regular wear.
• The gemstone has a refractive index of 1.746-1.755, providing excellent brilliance and light return when properly cut, while its vitreous to slightly greasy luster gives it a distinctive appearance even aside from its color-changing properties.
• Alexandrite crystallizes in the orthorhombic system and commonly forms as cyclic twins (known as “Russian twins”) with a distinctive hourglass-shaped cross-section that skilled cutters can use to maximize the stone’s color change properties.
• With a specific gravity of 3.73, alexandrite is noticeably heavier than many common gemstones, giving even small stones a satisfying weight and presence when held or worn in jewelry.
• Unlike many colored gemstones, alexandrite is generally free from cleavage planes (which can cause stones to split along certain directions), giving it excellent toughness and making it resistant to chipping even when subjected to impacts.
• Natural alexandrite typically contains characteristic inclusions that gemologists use for identification, including needle-like inclusions, liquid feathers, and growth tubes, with the “bread crumb” pattern being particularly distinctive of Russian alexandrite.

The physical durability of alexandrite means that even antique pieces featuring this gemstone often remain in excellent condition, maintaining their beauty and structural integrity over generations. This combination of impressive hardness, toughness, and optical properties makes alexandrite not just a curiosity for its color change but a genuinely superior gemstone by objective physical standards.

Alexandrite Mining Locations

Since its initial discovery in Russia’s Ural Mountains, alexandrite has been found in several locations around the world, though significant deposits remain extremely rare. Each location produces alexandrite with slightly different characteristics in terms of color change, clarity, and typical crystal size. The geographic origin of an alexandrite can significantly impact its value, with stones from certain regions commanding premium prices due to their superior quality or historical significance.

• The original Russian deposits in the Ural Mountains produced what many consider the finest alexandrite ever found, with a strong green to red color change and excellent clarity, though these mines have been largely depleted since the early 20th century, making Russian alexandrite exceedingly rare and valuable.
• Brazil became a significant source of alexandrite in the 1980s with the discovery of deposits in Minas Gerais state, particularly near Hematita and in the Novello mine, producing stones that typically show a blue-green to purplish-red color change rather than the emerald-to-ruby transformation of Russian material.
• Sri Lanka (formerly Ceylon) produces alexandrite with typically larger crystal sizes than other locations, though the color change is often less dramatic, showing brownish-green to reddish-purple shifts rather than the pure green-to-red transformation.
• Tanzania’s Tunduru district and Mozambique’s deposits have emerged as important sources in recent decades, with East African alexandrite sometimes rivaling Brazilian material in quality and showing good color change with attractive teal to purple-red transformations.
• Other notable sources include India (particularly the state of Andhra Pradesh), Madagascar (which produces small but often high-quality stones), and Myanmar (Burma), each with their own characteristic color profiles and quality ranges.
• Zimbabwe’s Novello mine occasionally produces alexandrite of exceptional quality, though in very limited quantities, with stones showing a distinctive bluish-green to magenta color change that has become highly sought after by collectors.

The global distribution of alexandrite deposits illustrates the extremely specific geological conditions required for its formation, including the precise combination of beryllium, aluminum, and chromium in an environment with the right pressure and temperature conditions. These strict requirements explain why alexandrite remains one of the rarest gemstones on Earth, with new significant deposits discovered only a handful of times in the nearly two centuries since its initial identification.

How Much Is Alexandrite Worth?

Alexandrite ranks among the most valuable colored gemstones in the world, often commanding higher per-carat prices than diamonds of similar size. This extraordinary value stems from a combination of extreme rarity in nature and the unique visual appeal of its color-changing properties. The market for fine alexandrite has remained strong even as other gemstone markets fluctuate, reflecting both its enduring appeal to collectors and its genuine scarcity in gem-quality sizes.

• Fine-quality natural alexandrite over one carat can easily sell for $15,000 to $30,000 per carat, with exceptional specimens of greater size or with Russian origin potentially commanding $50,000 to $100,000 per carat or more at auction.
• The primary value factors for alexandrite are the strength and completeness of the color change (with stones showing 100% shift from rich green to ruby red being most valuable), followed by size, clarity, cut quality, and geographic origin.
• Size dramatically impacts alexandrite pricing due to the exponential rarity of larger crystals, with the price per carat increasing dramatically as stones exceed one carat, making a 5-carat alexandrite potentially hundreds of times more valuable than five 1-carat stones of equal quality.
• Russian alexandrite commands a substantial premium due to its historical significance, superior color change, and extreme rarity, with documented specimens from the original Ural Mountain mines considered among the most collectible colored gemstones in existence.
• The global production of gem-quality alexandrite suitable for cutting into finished stones is estimated at less than one ton annually, compared to approximately 20,000 tons of diamonds and several thousand tons of other popular colored gemstones.
• Investment-grade alexandrite has shown strong appreciation over time, with documented cases of fine specimens increasing in value by 10-15% annually over the past several decades, outperforming many traditional investment vehicles.

The market for alexandrite remains primarily driven by knowledgeable collectors and connoisseurs rather than mass-market jewelry consumers, which has helped maintain its value through economic cycles. While synthetic alexandrite (created through various laboratory processes) is widely available at a fraction of the cost of natural stones, the market clearly distinguishes between these materials, with natural alexandrite maintaining its position as one of the most precious and sought-after colored gemstones in the world.

How to Clean Alexandrite Jewelry

Despite its excellent durability, proper care remains important for maintaining the beauty and integrity of alexandrite jewelry. The same exceptional properties that make alexandrite valuable – its color change effect and brilliant luster – deserve protection through appropriate handling, cleaning, and storage practices. With proper care, alexandrite jewelry can remain a treasured heirloom for generations, maintaining both its visual appeal and its significant value.

• Alexandrite can be safely cleaned using warm soapy water and a soft brush, with ultrasonic cleaners generally considered safe for solid alexandrite pieces without fragile settings or inclusions that might be affected by vibration.
• Steam cleaning should be approached with caution, particularly for alexandrite set in jewelry with adhesives or with surface-reaching inclusions that could be damaged by rapid temperature changes or moisture intrusion.
• Avoid exposing alexandrite jewelry to harsh chemicals including chlorine (found in swimming pools and household bleach), which won’t damage the alexandrite itself but can deteriorate metal settings and potentially loosen stones.
• Store alexandrite jewelry separately from other pieces to prevent scratching, ideally in individual soft cloth pouches or compartments in a jewelry box, as even though alexandrite is quite hard, it can still be scratched by diamonds and some synthetic materials.
• Regular professional inspection of settings is recommended for valuable alexandrite pieces, particularly rings that receive daily wear, as the high value of the stone justifies preventive maintenance to avoid loss from loose settings.
• When displaying or photographing alexandrite to appreciate its color change, have multiple light sources available – ideally natural daylight and incandescent lighting – to fully experience and demonstrate the stone’s remarkable color transformation.

With its exceptional hardness and lack of sensitivity to heat or light exposure, alexandrite is among the most durable colored gemstones available for jewelry. However, its significant value means that even minor damage can substantially impact its worth. Treating alexandrite jewelry with appropriate care ensures that both its beauty and value remain intact for future generations to enjoy.

Alexandrite as a June Birthstone

Alexandrite holds the distinction of being one of the modern birthstones for June, sharing this honor with pearl and moonstone. As a relatively recent addition to the standardized birthstone list, alexandrite brings its dramatic color-changing properties to those born in the early summer month. Its association with balance, regeneration, and good fortune makes it not just a visually striking birthstone but one rich with symbolic meaning that resonates with many born under its influence.

• Alexandrite became an official June birthstone in 1952 when the Jewelry Industry Council updated the modern birthstone list, adding this relatively recent gemstone discovery alongside the traditional pearl.
• As a birthstone, alexandrite is said to strengthen intuition, creativity, and imagination, with its color-changing nature symbolizing the ability to adapt to changing circumstances and see situations from multiple perspectives.
• In metaphysical traditions, alexandrite is associated with the crown chakra and is believed to help balance emotional states, particularly useful for those born in June who might experience the seasonal transitions between spring and summer more acutely.
• The gemstone’s dual nature – showing different colors in different environments – is thought to represent the duality within each person and the harmony that comes from embracing opposing aspects of one’s personality.
• For June-born individuals who prefer colored gemstones to pearls, alexandrite offers a durable alternative that can be set in any jewelry style, including everyday rings that might not be suitable for the more delicate pearl.
• As a gift for June birthdays, alexandrite carries special significance beyond its birthstone status, as it’s associated with the 55th wedding anniversary, symbolizing the enduring and ever-changing nature of long-lasting relationships.

The rarity and cost of fine natural alexandrite mean that many June-born individuals may opt for alternative versions of their birthstone, including laboratory-created alexandrite which faithfully reproduces the color-change effect at a fraction of the cost. However, for those fortunate enough to own natural alexandrite as their birthstone, they possess not just a beautiful gem but one of the most scientifically fascinating and visually dynamic stones in the gemological world.

Natural vs Lab-Created Alexandrite

With natural alexandrite commanding such extraordinary prices due to its rarity, laboratory-created alternatives have become increasingly popular for those who appreciate the stone’s unique properties but find natural specimens beyond their budget. Understanding the differences between natural and lab-created alexandrite helps consumers make informed decisions based on their priorities regarding appearance, value, and environmental considerations.

• Laboratory-created alexandrite reproduces the essential chemical composition and color-change effect of natural alexandrite through processes like the floating zone method, hydrothermal growth, or flux growth, creating gems that are chemically and physically identical to natural stones but formed in controlled environments.
• The primary visual difference between natural and lab-created alexandrite is that synthetic stones often show a more perfect and dramatic color change than all but the finest natural specimens, sometimes appearing “too perfect” to experienced gemologists familiar with the typical characteristics of natural material.
• Natural alexandrite typically contains characteristic inclusions that serve as “fingerprints” of its geological formation, while lab-created stones may be inclusion-free or contain distinctive inclusion patterns that reflect their manufacturing process, providing important identification markers.
• The price difference is substantial, with fine lab-created alexandrite typically selling for $100-500 per carat regardless of size, compared to thousands or tens of thousands per carat for natural stones, making the synthetic option accessible to a much wider market.
• Environmental and ethical considerations may favor lab-created alexandrite, as it requires no mining and has a significantly lower environmental footprint than extracted gemstones, though the energy requirements for crystal growth can still be substantial.
• While natural alexandrite tends to maintain or increase its value over time due to its extreme rarity, lab-created stones are primarily valued for their beauty rather than as investments, typically not appreciating in value despite their identical appearance to the untrained eye.

Both natural and laboratory-created alexandrite have their legitimate place in the jewelry market, serving different consumer needs and priorities. For those who value the romance, rarity, and investment potential of a gemstone forged by natural geological processes, natural alexandrite remains the clear choice despite its premium price. For those who primarily appreciate the unique color-changing properties and appearance at an accessible price point, lab-created alexandrite offers a practical alternative that delivers the visual excitement of this remarkable gemstone.

How to Identify Real Alexandrite

Given the significant value difference between natural alexandrite and its various imitations or synthetic counterparts, being able to identify authentic alexandrite is an important skill for potential buyers. While professional gemological testing remains the gold standard for definitive identification, understanding the key characteristics and simple tests can help consumers avoid obvious misrepresentations and make more informed purchasing decisions when considering an alexandrite acquisition.

• Genuine alexandrite’s color change is distinctive and consistent throughout the stone, typically showing green to teal in daylight transitioning to raspberry red or purplish-red in incandescent light, while many imitations show either less dramatic shifts or different color combinations entirely.
• Under a 10x loupe or microscope, natural alexandrite typically displays characteristic inclusions including fine parallel needle-like structures, “fingerprints” (healed fractures), and sometimes distinctive twinning planes, while many imitations show different inclusion patterns or none at all.
• Alexandrite’s refractive index range (1.746-1.755) and specific gravity (3.73) differ from similar-looking stones like color-change sapphire, garnet, or spinel, which can be measured by a gemologist using specialized equipment to confirm identification.
• Genuine alexandrite will scratch glass easily due to its 8.5 hardness, while softer imitations like color-change glass (hardness 5.5-6) or plastic imitations will not, though this test should be performed cautiously and only on the girdle of the stone to avoid damage.
• Polariscope testing reveals that alexandrite is doubly refractive (birefringent) with strong pleochroism, showing different colors when viewed from different angles, properties not shared by all potential imitations like cubic zirconia or glass.
• The Chelsea filter test can help identify alexandrite, as it will typically appear red through this specialized filter due to its chromium content, while many imitations will appear green or another color, though some genuine color-change sapphires may also test similarly.

For significant purchases, obtaining a professional gemological certificate from a respected laboratory like GIA, AGL, or SSEF provides the most reliable verification of authenticity and quality assessment. These reports typically include details about the stone’s natural or synthetic origin, treatment status, geographic origin (when determinable), and key quality characteristics. While such certification adds to the initial cost, it provides valuable documentation that can protect your investment and facilitate any future resale of the stone.

Conclusion

Alexandrite represents one of nature’s most remarkable optical phenomena encapsulated in gem form. From its dramatic discovery in Imperial Russia to its current status as one of the world’s most valuable colored gemstones, alexandrite continues to captivate with its chameleon-like ability to shift between colors. The gemstone’s combination of extreme rarity, exceptional durability, and unique visual properties ensures its enduring place among the most treasured materials in the jewelry world.

Whether appreciated as a June birthstone, a collector’s trophy, or simply as a beautiful addition to a jewelry collection, alexandrite offers something truly special – a gemstone that seems to transform its very essence as it moves between different environments, reminding us of nature’s endless capacity to surprise and delight. With proper care, alexandrite jewelry can be enjoyed for generations, maintaining both its remarkable beauty and its significant value as one of the rarest and most fascinating gemstones on Earth.