The Gem That Changes Its Mind
Alexandrite is a variety of chrysoberyl that performs one of nature's most remarkable optical tricks: it appears green in daylight and red or purplish-red under incandescent light. This dramatic colour change is caused by the presence of chromium in the crystal structure, which creates an absorption window that sits precisely between green and red wavelengths. Depending on the light source's spectral composition, the human eye perceives the dominant wavelength differently.
The strongest alexandrites display near-complete colour change — pure green in daylight, pure red under a candle or incandescent bulb. Such stones are extraordinarily rare. Most alexandrites show a weaker change: teal to brownish-red, or green to purple. The quality and completeness of the colour change is the primary value driver.
Russia: The Original and Finest
Alexandrite was first discovered in Russia's Ural Mountains in the 1830s, reputedly on the birthday of Tsar Alexander II — hence the name. The timing was fortuitous: green and red were the imperial Russian colours. Russian alexandrites were immediately adopted by the Romanov court and became one of the most prized stones of the 19th century.
The Ural deposit produced alexandrites with remarkable colour change — grass green to vivid red — and a clarity that allowed large, clean stones to be cut. The mine was largely exhausted by the early 20th century, and few new Ural stones enter the market today. Fine Russian alexandrites with strong colour change are among the rarest stones in the world; fewer than 1,000 fine specimens are estimated to exist in collectible condition.
Fine Russian alexandrite of 1 carat and above with strong colour change commands $30,000–$150,000 per carat, with exceptional stones exceeding this range.
Brazil: The Accessible Alternative
Brazil became a major alexandrite source in the 1980s when deposits were discovered in Minas Gerais state. Brazilian alexandrite is generally more affordable and more available. The colour change is typically weaker than Russian material — often a yellow-green to brownish-red — and the crystals tend to be slightly silkier. However, fine Brazilian alexandrites with strong colour change and good clarity can be stunning stones and sell for $3,000–$20,000 per carat.
Brazil currently supplies the majority of the world's alexandrite market and has made the stone accessible to a broader collector base.
Sri Lanka: The Bluish-Green Variant
Sri Lanka (Ceylon) produces alexandrites with a distinctive bluish-green or teal appearance in daylight, shifting to purplish-red under incandescent light. Ceylon alexandrites often have excellent clarity and can be found in larger sizes than Russian material. The colour change, while genuine, is generally less dramatic than the best Russian stones. Ceylon alexandrites sell for $2,000–$10,000 per carat depending on colour change strength.
Colour Change Strength
The value hierarchy for alexandrite is dominated by colour change completeness. Gemmologists assess colour change on a scale from "weak" (10–20% shift) to "strong" (60–80% shift) to "very strong" (>80% shift). A stone that is genuinely green in daylight and genuinely red under incandescent achieves the "very strong" designation and commands maximum premiums.
The origin is the secondary value driver: Russian > Brazilian/Ceylon for equivalent colour change quality.
Synthetic Alexandrite
Because natural alexandrite is so rare and expensive, synthetic alexandrite is common in the market. Flux-grown synthetic alexandrites show strong colour change but lack the geological characteristics of natural stones. Lab identification is essential for any stone above $1,000. Always require a GIA, Gübelin, or AGL report confirming natural origin before purchasing.
