Alexandrite is one of the rarest and most captivating gemstones in the world, renowned for its extraordinary ability to shift colors. A variety of chrysoberyl, alexandrite is famed for its color change—appearing green in daylight and transforming to red under incandescent light. This optical marvel, combined with the gemstone’s rarity, has made it highly sought after by collectors and enthusiasts.
This article delves into every aspect of alexandrite, from its formation and occurrence to the regions where the finest specimens are found, including Russia, Sri Lanka, and Brazil. We’ll also cover common inclusions, treatments that enhance its appearance, and the factors determining its value, such as clarity, cut, and carat weight. Lastly, we’ll explore its significance as the birthstone for June and its believed powers of emotional and physical healing.
1. Alexandrite: Formation & Occurrence
Alexandrite stones are a rare and valuable chrysoberyl, formed under specific geological conditions. The gemstone originates from areas where pegmatitic and metamorphic processes occur, allowing beryllium and chromium to come together, resulting in the gem's signature color change. It is found in primary and alluvial deposits, with major sources in Russia's Ural Mountains, Brazil, Sri Lanka, and India.
Rough Alexandrite (Source: GIA)
The presence of chromium is crucial to its color-changing ability, as this trace element replaces aluminum in alexandrite’s crystal lattice. The gem belongs to the orthorhombic crystal system, which, combined with its unique composition, causes light to refract differently under various conditions.
2. Where is Alexandrite Found?
Natural alexandrite is sourced from several key locations worldwide, each known for producing high-quality stones. Russia, particularly the Ural Mountains, was the first major source, discovered in the 1830s. Russian stones are prized for their strong green-to-red color shift and minimal inclusions, making them highly sought after in jewelry.
Russian Alexandrites are known to be of superior quality
In recent years, Brazil has become a significant player, with mines in Minas Gerais and Bahia producing larger stones with noticeable color shifts from bluish-green to purplish-red. These Brazilian stones are favored for their clarity and size, often used in fine earrings and necklaces. Sri Lanka produces gems with a softer color change, typically from blue-green to raspberry-red, and though smaller in size, they remain valuable for their rarity. India, particularly in Tamil Nadu and Andhra Pradesh, produces alexandrite stones with a green-to-brownish-red shift.
Other notable locations include Madagascar, Tanzania, and Myanmar, but the finest gems still come from Russia and Brazil, where quality alexandrite with strong colour change is consistently found.
3. Color Changing Properties of Alexandrite
The defining trait of an alexandrite stone is its remarkable color change. This phenomenon is caused by trace elements within the gem’s crystal structure. In daylight, the stone absorbs green and blue wavelengths of light, producing its characteristic green color. When exposed to incandescent light, richer in red wavelengths, the stone reflects deep red hues, giving the stone its famous color-shifting property.
Alexandrites stand as the epitome of color-change gemstones (Source: GIA)
The intensity and shades of this color shift vary based on the concentration of these trace elements. Higher levels of the trace element result in more pronounced and dramatic colour changes. However, additional elements like iron or titanium can influence the exact hues, sometimes muting the color change or introducing secondary tones, such as brown. Quality alexandrite gemstones with minimal blending between hues are particularly valuable, especially when set in jewelry like earrings and rings. The geographic origin of the gem also plays a key role in the stone’s color variations:
- Russia: Russian stones exhibit a sharp green-to-red shift, often with intense color saturation.
- Sri Lanka: Stones show a gentler bluish-green to raspberry-red transition, with softer shifts but valued for their rarity.
- Brazil: Brazilian stones display a bluish-green to purplish-red color change and are known for their larger sizes and higher clarity.
- Tanzania: These gems tend to shift from green to brownish-red, with more subtle color variations.
- India: The stones show a green-to-brownish-red shift similar to those from Tanzania, often with a muted color change but still desirable due to their scarcity.
4. Common Inclusions in Alexandrite
Like many natural gemstones such as peridot and opal, alexandrite may contain internal characteristics that develop during its formation. Among the most common inclusions in alexandrites are rutile needles, which are thin, needle-like formations of titanium dioxide. These can sometimes produce a star-like visual effect called asterism, which adds to the gemstone’s beauty. However, if too densely packed, they can cloud the stone and lower its clarity.
Crystal inclusions in an Alexandrite (ruby-sapphire.com)
Fingerprint inclusions, which resemble the swirls of a fingerprint, are also commonly found. These are typically fluid-filled and form as the gemstone undergoes internal pressure changes during growth. While they are usually small, their visibility can affect the overall clarity of the stone.
Another common one is color zoning, where the stone may show uneven color distribution, often due to variations in trace element concentrations during its growth. This zoning can be subtle or more pronounced, potentially reducing the gemstone's value if it impacts the color-changing effect.
Growth lines, which form as the crystal grows, are generally acceptable unless they interfere with the stone’s optical properties. Additionally, small crystals of other trapped minerals may be seen, but if they are too large or numerous, they can reduce the overall value of the gemstone. Overall stones with minimal internal features are considered more valuable, especially when verified by lab testing. Stones with greater clarity, especially those showing a strong color change, often command higher prices.
5. Common Treatments & Enhancements for Alexandrite
While natural alexandrite stones are highly prized, certain treatments are used to enhance their appearance, particularly when clarity is compromised or the color change is less vivid. The following are the most common treatments:
- Heat Treatment: This is commonly used to improve both clarity and enhance the stone’s green-to-red shift. The process involves heating the stone to dissolve internal flaws, which enhances overall transparency. However, if not carefully monitored, this treatment can alter the stone’s natural balance of colors.
- Fracture Filling: In this method, a clear resin or glass-like material is injected into surface-reaching cracks to enhance the gem’s appearance. Although fracture filling does not affect the colour-changing properties, stones that undergo this treatment are generally considered less valuable than untreated counterparts.
In high-end jewelry, particularly for pieces like earrings, natural alexandrite with strong color shifts and excellent clarity is far more desirable than treated stones, as untreated gems hold higher value in the market.
| Mineral | Chrysoberyl |
|---|---|
| Colour Range | Green to Red (bluish-green in daylight, purplish-red in incandescent light) |
| Popular Origins | Russia, Brazil, Sri Lanka, India, Tanzania |
| Mohs Hardness | 8.50 (on a scale of 10) |
| Common Treatments | Heat treatment/Thermal enhancement; Fracture-filling |
| Birthstone | June |
Alexandrites - A Quick Snapshot
6. Evaluating the Quality of Alexandrite
Evaluating alexandrite involves four key factors, known as the 4Cs: color, clarity, cut, and carat weight.
- Color: The most important factor is the gemstone’s color change. Stones that shift sharply from green to red are the most valuable. Stones with vivid and intense colors are especially prized by collectors.
- Clarity: Most natural alexandrite stones contain internal characteristics, but eye-clean stones with minimal features are extremely rare and command premium prices. Internal features like small crystals or rutile needles are acceptable if they don’t interfere with the stone’s color change, but larger inclusions can lower its value.
- Cut: The cut enhances the stone's beauty and color-shifting effects. Alexandrite is often cut into shapes like oval, cushion, or emerald cuts to emphasize its pleochroic properties, allowing the green and red hues to stand out.
- Carat Weight: Carat weight significantly affects the stone’s value. Alexandrites larger than 1 carat are rare, and those over 5 carats are especially valuable, with prices increasing dramatically for stones with strong color change and excellent clarity.
7. How Much Does Alexandrite Cost?
The price of alexandrite gemstones can vary significantly depending on factors like color change, clarity, origin, and carat weight. Lower-quality stones with weak color shifts are priced below $2,000 per carat, while mid-range stones with about a 50-60% color change can range from $7,000 to $20,000 per carat.
Top-quality stones with an 80-100% color shift are exceedingly rare and can exceed $20,000 per carat, especially for stones larger than 1 carat. Larger stones, particularly those over 5 carats, are highly sought after and can fetch more than $50,000 per carat, especially if they exhibit strong color-changing properties from Russia or Brazil.
8. Alexandrite in Astrology
As the birthstone for June, alexandrite is cherished in astrology for symbolizing balance, creativity, and good fortune. Its unique color-shifting ability from green to red is seen as a reflection of transformation and renewal, making it an ideal stone for those undergoing life changes. The gemstone is believed to aid in emotional healing, offering calmness and inner peace to its wearer. Just like opal, alexandrite is also thought to assist in aligning the heart and crown chakras, promoting emotional balance and reducing stress.
In spiritual practices, the stone is considered a stone that enhances intuition and supports spiritual growth, helping individuals connect with their inner selves. This makes it popular among those seeking clarity, balance, and a deeper understanding of their life’s path. Its association with prosperity and personal transformation makes it a powerful talisman for embracing change while maintaining equilibrium. Whether worn for its mystical properties or its beauty, the gem is a symbol of growth, renewal, and harmony.
Conclusive Reflections
Alexandrite stands as one of the most fascinating and rare gemstones, celebrated for its remarkable color-changing properties and rich history. Whether admired for its scientific uniqueness or its mystical qualities, alexandrite continues to inspire wonder and fascination. Its rarity, combined with its ability to symbolize personal growth and renewal, makes it a treasured gemstone among collectors and enthusiasts alike.
At Precious Earth, we pride ourselves on offering a wide selection of rare and high-quality gemstones, including amethyst, moonstone, alexandrite, peridot, garnet, tourmaline, opal and sapphire. Each stone is carefully sourced to ensure its authenticity and brilliance, making them perfect for collectors or for creating custom earrings or other personalized pieces. Whether you're drawn to the striking color change of alexandrite or the vibrant hues of topaz, sapphire and tourmaline, our collection guarantees that you'll find a gemstone that speaks to your unique tastes.
