Alexandrite Buying Guide: Natural Colour-Change Chrysoberyl

What Is Alexandrite?

Alexandrite is one of nature's most remarkable gemstones, a rare variety of chrysoberyl that displays a dramatic colour-change phenomenon depending on the light source. Under daylight or fluorescent lighting, alexandrite appears green to bluish-green. Under incandescent light (traditional tungsten bulbs or candlelight), the same stone transforms to red, purplish-red, or raspberry hues. This mesmerizing optical effect has captivated collectors and connoisseurs since the stone's discovery nearly two centuries ago.

The colour-change in alexandrite is caused by the presence of chromium impurities within the chrysoberyl crystal structure (beryllium aluminum oxide, BeAl₂O₄). Chromium absorbs light in the yellow portion of the visible spectrum, allowing both green and red wavelengths to be transmitted. The relative intensity of these wavelengths in different light sources determines which colour dominates. Daylight is rich in blue-green wavelengths, causing the stone to appear green. Incandescent light is rich in red wavelengths, causing the red appearance to dominate.

This phenomenon is distinct from pleochroism (the display of different colours when viewed from different angles), though alexandrite also exhibits pleochroism. The colour-change is a true transformation based on light source composition, making alexandrite one of the most fascinating gemstones in the world of fine jewelry.

Historic Discovery and the Russian Connection

Alexandrite was discovered in the Ural Mountains of Russia in the 1830s, with most accounts placing the discovery around 1834. According to gemological lore, the stone was found in emerald mines near the Tokovaya River on the day that the future Tsar Alexander II came of age, and was subsequently named in his honour. The timing was fortuitous—the stone's colour-change from green to red mirrored the military colours of Imperial Russia, making it an instant symbol of Russian national pride.

The original Russian deposits produced alexandrite with particularly strong colour-change, typically from a fine bluish-green in daylight to a purplish-red under incandescent light. These stones set the standard by which all subsequent alexandrite discoveries have been judged. Russian alexandrite quickly became one of the most prized gemstones among European royalty and aristocracy during the 19th century.

The Russian Ural Mountain deposits were never abundant and became largely depleted by the early 20th century. Today, Russian alexandrite of fine quality is exceedingly rare in the market, and documented Russian provenance adds a significant premium to already high prices. Antique jewelry containing original Russian alexandrite is highly sought after by collectors.

Modern Sources of Alexandrite

Following the depletion of Russian deposits, alexandrite has been discovered in several other locations around the world, though fine-quality material remains rare from all sources.

Sri Lanka (Ceylon)

Sri Lanka has produced alexandrite since the mid-20th century, primarily from the gem gravels of Ratnapura and surrounding districts. Sri Lankan alexandrite tends to show a colour-change from yellowish-green or olive-green in daylight to brownish-red or orangish-red under incandescent light. While the colour-change is often less dramatic than the finest Russian or Brazilian material, Sri Lankan alexandrite can be found in larger sizes and with good clarity. During my 28 years of sourcing in Sri Lanka since 1998, I have encountered Sri Lankan alexandrite regularly, though truly fine specimens with strong colour-change remain uncommon.

Brazil—Hematita, Minas Gerais

The discovery of alexandrite in Hematita, Minas Gerais, Brazil, in the 1980s was a significant event in the gem world. Brazilian alexandrite from this locality can rival the finest Russian material, displaying strong colour-change from bluish-green to purplish-red. The Hematita deposits produced some of the finest alexandrite seen in decades, though production has been sporadic and fine material is now scarce. Brazilian alexandrite set a new standard for modern alexandrite and demonstrated that exceptional quality was not limited to historical Russian sources.

Tanzania—Lake Manyara Region

Tanzanian alexandrite was discovered in the 1960s near Lake Manyara in northern Tanzania. Tanzanian material typically shows a colour-change from bluish-green to purplish-red, though the intensity of change varies considerably. Some Tanzanian alexandrite exhibits a strong colour-change comparable to fine Russian or Brazilian stones, while other material shows only moderate change. Tanzanian alexandrite is often found in smaller sizes, with stones over 2 carats being uncommon.

India—Andhra Pradesh

Alexandrite has been found in Andhra Pradesh, India, though production has been limited and inconsistent. Indian alexandrite typically shows moderate colour-change and is generally found in smaller sizes. While not as celebrated as material from other sources, Indian alexandrite can offer good value for collectors seeking smaller stones with acceptable colour-change.

Colour-Change Quality Grading

The strength and character of the colour-change is the single most important factor in evaluating alexandrite quality and value. Gemologists and dealers classify colour-change into several categories:

Strong Colour-Change

Strong colour-change alexandrite displays a dramatic transformation from a distinct green (ideally bluish-green) in daylight to a distinct red (ideally purplish-red) under incandescent light. The two colours should be clearly different, with minimal overlap in hue. Strong colour-change alexandrite represents the finest quality and commands the highest prices. The classic description "emerald by day, ruby by night" applies to the best examples of strong colour-change alexandrite.

Moderate Colour-Change

Moderate colour-change alexandrite shows a noticeable shift between light sources, but the change is less dramatic. The stone might shift from yellowish-green to brownish-red, or from grayish-green to purplish-brown. While the colour-change is observable, it lacks the striking contrast of strong colour-change material. Moderate colour-change alexandrite is more common than strong colour-change and is priced accordingly, typically at 40-60% of the value of comparable strong colour-change stones.

Weak Colour-Change

Weak colour-change alexandrite displays only a subtle shift between light sources, often requiring careful observation to detect. These stones might shift from grayish-green to grayish-red, or show only a slight change in tone rather than hue. Weak colour-change alexandrite is the most common and least valuable, though it is still genuine alexandrite and may appeal to collectors on a budget.

Beyond colour-change strength, clarity, cut quality, and size all affect value. Alexandrite with strong colour-change, excellent clarity (eye-clean), fine cutting, and size over 1 carat represents the pinnacle of quality and rarity.

Treatments and Synthetic Alexandrite

Natural Alexandrite Treatment

Natural alexandrite is almost always untreated. Unlike many other gemstones, no effective treatments exist to enhance alexandrite's colour or colour-change. Heat treatment does not improve alexandrite, and other enhancement methods are not applied. This is one of the appealing aspects of alexandrite for collectors—what you see is what nature created.

Synthetic Alexandrite History

Synthetic alexandrite has been produced since the 1960s using various methods, most commonly the Czochralski pulled-growth technique and flux-melt growth. Czochralski-grown synthetic alexandrite became commercially available in the 1960s and 1970s, and these synthetics can display excellent colour-change that rivals natural stones. Flux-melt synthetic alexandrite, grown more slowly in a molten flux medium, can be even more challenging to distinguish from natural material.

The availability of synthetic alexandrite has complicated the market significantly. Many jewelry pieces from the 1960s onward contain synthetic alexandrite, sometimes represented as natural. Synthetic alexandrite is not inherently problematic—it is a legitimate product when properly disclosed—but undisclosed synthetic material sold as natural constitutes fraud and has damaged consumer confidence.

Distinguishing Natural from Synthetic

Professional gemological testing is essential for valuable alexandrite. Natural alexandrite typically contains characteristic inclusions such as needle-like crystals, fingerprint patterns (healed fractures), and two-phase inclusions (liquid and gas). These inclusions, while potentially affecting clarity, serve as evidence of natural origin.

Czochralski-grown synthetic alexandrite often displays curved growth lines visible under magnification, a telltale sign of the pulled-growth process. These curved lines are not found in natural alexandrite. Flux-melt synthetics may contain flux fingerprints, wispy veils, and metallic flux inclusions that differ from natural inclusion patterns.

Refractive index measurements can also provide clues, as some synthetic alexandrite shows slightly different optical properties than natural material. However, inclusion study under magnification remains the primary method for distinguishing natural from synthetic alexandrite.

For any alexandrite purchase of significant value, I strongly recommend obtaining a laboratory report from GIA (Gemological Institute of America) or another reputable gemological laboratory. The report should specifically identify the stone as natural and note whether colour-change is present. At SkyJems, we are long-standing clients of GIA Hong Kong (account 25922011) and routinely submit valuable alexandrite for certification.

Alexandrite Pricing in 2026

Natural alexandrite with strong colour-change is among the most expensive coloured gemstones in the world. Pricing in 2026 reflects both the extreme rarity of fine material and strong collector demand.

For alexandrite with moderate colour-change under 1 carat, expect to pay approximately $3,000 to $8,000 CAD per carat, depending on clarity, cut quality, and specific colour-change characteristics. Stones in the 1-2 carat range with moderate colour-change typically range from $5,000 to $12,000 CAD per carat.

Alexandrite with strong colour-change over 1 carat can exceed $20,000 CAD per carat, with exceptional examples reaching $30,000 to $50,000 CAD per carat or more. Russian alexandrite with documented provenance commands additional premium, sometimes 20-40% above comparable material from other sources. Brazilian alexandrite from Hematita with strong colour-change rivals Russian material in both quality and price.

Stones over 3 carats with strong colour-change and fine clarity are exceptionally rare and are typically sold through auction houses or private treaty, with prices often exceeding $50,000 CAD per carat. Such stones are investment-grade gems and are acquired primarily by serious collectors.

Alexandrite with weak colour-change or significant clarity issues may be available for $1,000 to $3,000 CAD per carat, offering an entry point for collectors who appreciate the stone's rarity but have budget constraints.

It is worth noting that alexandrite pricing has increased steadily over the past two decades as fine material has become scarcer and collector interest has grown. Alexandrite represents not only a beautiful gemstone but also a tangible asset with strong long-term value retention.

Cat's-Eye Alexandrite: The Rarest Variety

Cat's-eye alexandrite represents the ultimate rarity in the alexandrite world—a stone that combines both the colour-change phenomenon and chatoyancy (the cat's-eye effect). Chatoyancy is caused by parallel needle-like inclusions within the crystal that reflect light in a concentrated band across the surface of a cabochon-cut stone.

Cat's-eye alexandrite must be cut en cabochon (with a domed, polished surface rather than facets) to display the eye effect. When properly cut and oriented, the stone displays a sharp band of light that moves across the surface as the stone or light source moves, resembling the slit pupil of a cat's eye.

Finding alexandrite with both strong colour-change and a sharp, well-centered cat's-eye is exceptionally rare. Most cat's-eye alexandrite originates from Sri Lanka or Brazil, with Sri Lankan material being more commonly encountered. The colour-change in cat's-eye alexandrite is often less dramatic than in faceted material, typically shifting from grayish-green to grayish-red or brownish-red.

Cat's-eye alexandrite with strong colour-change and a sharp eye commands significant premiums over faceted alexandrite of comparable size, often 50-100% more. Stones over 5 carats with excellent eye and strong colour-change are museum-quality rarities that seldom appear on the market.

GIA Reports and the Trade

In the alexandrite trade, laboratory reports from GIA (Gemological Institute of America) are considered the gold standard for authentication and quality assessment. A GIA report will identify whether a stone is natural or synthetic, confirm the presence of colour-change, and note any treatments (though treatment of natural alexandrite is virtually unknown).

For alexandrite over 1 carat with strong colour-change, a GIA report is essential for resale value and buyer confidence. The cost of a GIA report (typically $150-$300 CAD depending on stone size and service level) is a small investment relative to the value of the stone and provides crucial documentation.

Other reputable laboratories such as AGL (American Gemological Laboratories), Gübelin, and SSEF also provide excellent reports for alexandrite, particularly for stones with documented Russian origin. These laboratories may provide more detailed origin determination and historical context than standard GIA reports.

In the trade, alexandrite is typically sold with the understanding that colour-change strength is the primary value determinant. Dealers will often demonstrate the colour-change using both daylight-equivalent and incandescent light sources, allowing buyers to assess the strength and character of the change. Reputable dealers will always disclose whether a stone is natural or synthetic, and will provide laboratory documentation for valuable natural stones.

Conclusion: Acquiring Alexandrite with Confidence

Alexandrite remains one of the most fascinating and valuable gemstones available to collectors and jewelry enthusiasts. Its remarkable colour-change, historical significance, and extreme rarity combine to create a gemstone of enduring appeal and investment potential.

When acquiring alexandrite, prioritize colour-change strength above all other factors. A smaller stone with strong colour-change is preferable to a larger stone with weak change. Always insist on laboratory documentation for stones of significant value, and work with established dealers who have deep experience in the coloured gemstone trade.

At SkyJems, our family has been serving Canadian clients for 59 years of continuous operation since our founding in 1967. My father operated our Bogota office for 31 years (1985-2016), and I have personally sourced gemstones in Bangkok and Sri Lanka for 28 years since 1998. My mother, Linda Saad, continues as a second-generation principal, and our Operations Manager, Leila Haikonen, brings extensive experience from her former role as Manager of the Canadian Diamond Bourse. Our nomination for the 2024 CJA Lifetime Achievement Award reflects our commitment to integrity and expertise in the Canadian gem trade.

We invite you to contact us to discuss alexandrite acquisition, whether you are seeking a stone for a custom jewelry piece or adding to a collection. Our direct sourcing relationships and gemological expertise ensure that you receive authentic, accurately represented alexandrite of the quality you expect.