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Alexandrite Color Change Explained

Justin Zaroovabeli
April 5, 2024

Ever wondered why the alexandrite gemstone shifts from greenish-blue to purple-red as the lighting changes? This phenomenon stems from the interplay between its unique internal features and the surrounding light. Join us as we explore the “alexandrite color change,” illuminating the simple science behind this gem’s magical hues, without diving too deeply into scientific complexity.

The Science Behind Alexandrite's Color Change

purple alexandrite

The enchanting phenomenon of Alexandrite’s color change is not a result of pleochroism, where a gemstone displays different colors when viewed at varying angles. Instead, it’s a consequence of the stone’s unique light-absorbing properties, giving rise to the ‘emerald by day, ruby by night’ effect. This captivating dance of hues is influenced by the cut of the stone, which affects its absorption properties, intensifying or diminishing the clarity of the color change.

The intrigue deepens when you discover the role of chromium impurities within the chemical composition of the Alexandrite stone. These minute impurities are responsible for the stone’s color-changing properties, as they cause intense absorption of light over specific wavelengths. This means that regardless of the viewing angle, the color of Alexandrite is perceived uniformly by observers, thanks to angles above 20 degrees, which underlie the color constancy of the human visual system.

Chemical Composition

Delving further into the heart of the Alexandrite stone, the chemistry behind its color variations becomes apparent. The key player here is the chromium ion. In the chemical structure of Alexandrite, chromium ions replace a portion of aluminum ions, a phenomenon that triggers the stone’s distinctive color change. Intriguingly, a mere presence of less than 1 percent of chromium ions at aluminum sites is enough to give Alexandrite its distinctive colors.

These chromium ions absorb strongly in the dark blue and yellow regions of the visible light spectrum, affecting the color that Alexandrite exhibits under different lighting conditions. This absorption manifests as a change in color, from a green or blue-green hue in daylight to a captivating purplish-red or ruby red under incandescent light.

Crystal Structure

The secret behind the mesmerizing color-play of Alexandrite lies not only in its chemical composition but also in its crystal structure. The unique structure of the gemstone results in pleochroism, a property that causes them to show different colors when viewed from varying angles.

The typical colors observed in Alexandrite due to its pleochroic nature are green, orange, and purplish-red when viewed from various angles. This means that a single Alexandrite stone can display a veritable rainbow of colors, depending on the angle from which you gaze upon it. A truly magical phenomenon, wouldn’t you agree?

The Role of Light Sources in Alexandrite's Color Shift

All natural alexandrite showcasing both colors

The mesmerizing color shifts of an Alexandrite stone are not solely due to its internal properties. External factors, particularly different light sources, play a pivotal role in this captivating spectacle. Whether it’s the soft glow of daylight or the warm flicker of incandescent light, each light source, including ambient lighting, interacts uniquely with the Alexandrite, revealing a different color.

The vibrancy of the red or purple exhibited by Alexandrite in contrast with a deep bluish-green is an indication of a higher quality of color change. It’s this unique ability to shift colors from green to red that adds to the allure of Alexandrite. In fact, a reddish color change commands a significant premium due to its rarity and intensity.

Natural Daylight

Under the clear, natural daylight, Alexandrite exhibits a green to bluish-green hue. This color change is due to the absorption of dark blue and yellow light by chromium ions within the stone. The intensity of this color change in natural daylight typically ranges from moderate to strong in saturation, depending on the quality of the stone.

Interestingly, the Brazilian varieties of Alexandrite can show a color change from green to bluish-green in daylight, akin to the color change seen in the highly prized Russian Alexandrite. Thus, the spectacle of Alexandrite’s color change is not confined to a single geographic location but can be enjoyed worldwide.

Incandescent Light

When exposed to the warm tones of incandescent light, Alexandrite reveals a very different side of its personality. The stone appears purplish-red or ruby red, offering an enchanting contrast to its daylight hues. This shift in color is due to the pronounced red spectrum of incandescent light, which results in Alexandrite displaying purplish-red hues due to the lower absorption of red light by chromium ions.

When viewed under the warm light of lamps or even the flickering flame of candles, Alexandrite can change to a brownish-red or purplish-red hue. This dramatic shift in color under different lighting conditions is part of what makes Alexandrite so captivating and unique.

Fluorescent Light

Under the glow of natural daylight or fluorescent light, Alexandrite exhibits its pleochroic color of green. However, the real spectacle unfolds when Alexandrite is exposed to ultraviolet light. In such a light, the stone can display an intense, glowing red color. This is due to the absorption and release of energy by chromium ions within the stone.

This remarkable display of color under fluorescent light further heightens the allure of Alexandrite. Its ability to morph from a cool, calm emerald green under natural light to a fiery, intense red under ultraviolet light is nothing short of magical, proving once again why Alexandrite is one of the most unique and sought-after gemstones in the world.

Quality Factors Affecting Alexandrite's Color Change

Oval shaped green alexandrite

The strength and visual appeal of the color change in Alexandrite stones, also known as the alexandrite effect, can vary significantly. Various factors influence this change, such as the intensity of color saturation, transparency, and the cut of the stone. For instance, stones that are too light in color may not exhibit the intensity seen in higher quality Alexandrites, while stones that are too dark may lack brightness and appear almost black.

The color change also varies depending on the geographical origin of the Alexandrite. For example, some Alexandrites from Sri Lanka may exhibit a color change to yellowish greens or brownish reds. These hues are considered less desirable than the blue-green and purplish-red seen in more valued specimens, such as those from the Ural Mountains in Russia.

Intensity of Color Change

The intensity of color change in an Alexandrite stone is a significant factor in determining its value and desirability. The intensity of color saturation significantly influences the quality of Alexandrite’s color change.

A pronounced and vivid color change, especially in Alexandrite from the Ural Mountains in Russia, is highly desirable and crucial in determining the gemstone’s value. These stones are prized due to their historical significance and superior color-changing qualities. Such distinct color transformations not only add to the allure of Ural Mountains Alexandrite but also elevate its status as a coveted gemstone treasured by collectors and connoisseurs alike.

Clarity and Cut

Clarity and cut are two other key factors that can enhance the visibility of Alexandrite’s pleochroic color shifts and increase its value. A gemstone with high clarity and minimal inclusions showcases a pronounced color change, making the Alexandrite’s remarkable feature more pronounced. Greater clarity in an Alexandrite stone directly contributes to a more distinct and visible color change.

Cutting techniques also play a significant role in maximizing the visibility of Alexandrite’s pleochroic color shifts. Techniques that add facets and mixed cuts, such as combining brilliant-cut crowns with step-cut pavilions, are used to enhance the color shifts. Popular shapes for cutting Alexandrite include:

  • Round
  • Oval
  • Emerald
  • Pear
  • Marquise

Origins and Rarity of Natural Alexandrite

Ural Mountains of Russia

Alexandrite is a gemstone steeped in history and shrouded in rarity. Here are some key facts about this beautiful gemstone:

  • First discovered in the Ural Mountains of Russia
  • Named in honor of Czar Alexander II
  • Became an emblem of royalty due to its remarkable green and red colors, echoing the hues of the Russian military uniform

However, natural Alexandrite is rare, and the original Russian deposits have almost been depleted, making large uncut stones particularly scarce. The scarcity and unique color-changing properties of natural alexandrites have only added to its allure and value over the years.

Discovery and History

The discovery of Alexandrite in the 1830s marked a significant moment in gemstone history. The rich emerald mines in Russia’s Ural Mountains unveiled a gemstone like no other, exhibiting a dramatic color change under different light sources. This discovery coincided with the future Tsar Alexander II’s birthday, which was significant in garnering interest and esteem for the stone.

Named in honor of Czar Alexander II by the Russian mineralogist Nils Gustaf Nordenskiöld, Alexandrite became an emblem of Russian royalty. Its distinctive green and red colors, reflecting the hues of the Russian military uniform, further cemented its place in the annals of Russian history.

Geographic Origins

The historical narrative of Alexandrite intertwines deeply with Russia, yet its illustrious journey spans continents and cultures, echoing the marvels of discovery across diverse landscapes. Following the exhaustion of the original Russian troves, the quest for Alexandrite's elusive beauty led prospectors to distant corners of the globe, unearthing gemstone treasures in the verdant valleys of Brazil, the sun-kissed shores of Sri Lanka, and the rugged terrains of East Africa. However, amidst these vast expanses, the pursuit of top-tier Alexandrite persists as a testament to its enduring allure, with genuine high-quality specimens remaining a rarity, underscoring the gemstone's revered status among aficionados.

Beyond the primary sources, the story of Alexandrite unfolds in unexpected locales, with secondary deposits unveiling themselves in the meandering riverbeds of India, where alluvial riches whisper tales of hidden treasures, and in the vicinity of Tanzania's Lake Manyara, where the earth yields its own precious bounty. Despite the widespread dispersion of Alexandrite across continents, its scarcity remains unwavering, cementing its reputation as one of the most coveted jewels in the world, cherished for its unparalleled beauty and captivating color-changing properties. In this ever-evolving landscape of gemstone discovery, Alexandrite stands as a beacon of rarity, beckoning seekers of beauty and collectors alike to marvel at its timeless splendor.

The Allure of Alexandrite: Symbolism and Meaning

Alexandrite showing both green and purple colors

Beyond its captivating color change and rarity, Alexandrite holds deep symbolism and meaning. The gemstone symbolizes:

  • Fulfillment
  • A zest for adventure
  • Balance
  • Harmony
  • Love

It is often associated with luck, prosperity, and personal growth, making it a cherished stone for many. As the birthstone of June, Alexandrite is considered a perfect gift for those born in this month and is also a token for celebrating a 55th anniversary.

Whether it’s for its unique color-changing properties, its historical significance, or its symbolic meaning, Alexandrite holds a special allure that transcends the traditional confines of gemstones. Its captivating spectacle of color change, combined with its rarity and rich history, makes it a truly wonderful gemstone.

Gemstone Symbolism

In the 19th century Russia, Alexandrite was highly esteemed as a bringer of good luck, due to its connections with nobility and royalty. The distinctive color change from green to red in Alexandrite represents the symbolic balance between opposites, reflecting the ebb and flow of life itself, much like a green light that signals the perfect moment to move forward.

In modern times, this unique attribute of Alexandrite’s color change is celebrated in jewelry, especially to commemorate significant life milestones. It serves as a symbol of transformation and growth, with its shifting hues reflecting the ever-changing nature of our lives and experiences.

Alexandrite in Jewelry

The unique color-changing ability of Alexandrite makes it a sought-after feature in jewelry, perfectly enhancing a variety of styles for multiple occasions. Its remarkable ability to change color from green to red elevates the beauty and allure of jewelry pieces. It’s a gemstone of choice for rings, pendants, and other adornments, offering a dynamic and captivating visual experience unlike any other.

Increasingly, Alexandrite is becoming a popular choice in jewelry, even surpassing traditional gems like diamonds. Its bold colors and unique aesthetic possibilities make it a gemstone that not only captivates the eye but also tells a story of rarity, transformation, and enchantment.

Caring for Your Alexandrite Gemstones

Jewelry in jewelry box

While Alexandrite is a dazzling spectacle to behold, it also requires delicate care. Proper care for Alexandrite gemstones includes avoiding harsh chemicals, sudden temperature changes, and rough treatment, which could damage the gemstone or affect its color-changing properties.

Furthermore, cleaning your Alexandrite gemstone with warm soapy water and a soft cloth can help maintain its beauty and brilliance. Proper storage in a soft, padded jewelry box or a fabric-lined case can also prevent scratches and damage from environmental factors.

Cleaning and Storage

Maintaining the beauty and integrity of your Alexandrite gemstone involves regular cleaning and proper storage. Alexandrite should be cleaned with warm soapy water using a soft brush or cloth, ensuring that harsh treatments like ultrasonic cleaners or steamers are avoided. After cleaning, Alexandrite pieces need to be thoroughly dried before storage or wear to ensure the gemstone’s appearance is maintained.

For storage, it is advisable to store Alexandrite separately from other pieces of jewelry in a soft, padded environment such as a velveteen bag or a padded box. This prevents scratches and other damage, helping to preserve the gemstone’s beauty and longevity.

Avoiding Damage

Protecting Alexandrite from damage requires mindful handling and awareness of potential hazards. Alexandrite should not be exposed to harsh chemicals like bleach or ammonia, as they can cause harm. Sudden temperature changes should also be avoided to prevent damage to the gemstone.

Direct sunlight over prolonged periods can cause the color of Alexandrite to fade, so it’s best to store your gemstone in a location that does not receive direct sunlight for extended periods. Furthermore, handling Alexandrite gently and avoiding rough treatment can prevent potential scratches or other forms of damage.


Embarking on our enchanting journey through the mesmerizing realm of Alexandrite, we've delved into the intricate science governing its captivating color metamorphosis, scrutinized the pivotal influence of various light sources, scrutinized the myriad factors dictating the caliber of its color transformation, and marveled at the origins and scarcity intrinsic to this exceptional gem. Throughout our exploration, we've unraveled the profound symbolism and irresistible allure woven into the very fabric of Alexandrite, whilst also gaining insights into the meticulous care essential for preserving these precious stones. 

As our odyssey has unfolded, it has become abundantly clear that Alexandrite transcends the confines of mere gemstone status; it emerges as a breathtaking spectacle of nature, embodying the essence of equilibrium and evolution, and standing as a timeless relic of bygone eras. Whether one finds themselves immersed in the intricacies of gemology or simply drawn to the splendor of beauty, the spellbinding magnetism of Alexandrite remains undeniable, beckoning admirers from all walks of life to behold its timeless charm.

Frequently Asked Questions

What is the full color change of alexandrite?

The complete spectrum of color change exhibited by alexandrite ranges from a mesmerizing emerald green under natural daylight to a captivating ruby red under incandescent lighting, showcasing the gemstone's remarkable and rare ability to undergo an extraordinary transition contingent upon the surrounding ambient illumination.

Why does Alexandrite change color?

The color change in alexandrite is due to its unique light-absorbing properties, which are influenced by chromium impurities in its chemical structure. This causes the gem to appear green in natural light and red under incandescent light.

How does the intensity of color saturation affect Alexandrite's color change?

The intensity of color saturation significantly influences the quality of Alexandrite's color change, as stones that are too light or too dark may not exhibit the ideal intensity. Therefore, it is important to consider the intensity of color saturation when evaluating an Alexandrite's color change.

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