Alexandrite is one of the world’s most desired gemstones, prized for its extreme rarity and unique optical properties. The stone’s defining characteristic is its dramatic shift in appearance, known as the “Alexandrite effect,” which causes it to display a different color depending on the light source. Under natural daylight, the stone typically appears green or bluish-green, but when exposed to incandescent light, it transforms into a distinct red or purplish-red hue. This dual nature is a result of trace amounts of chromium ions within the chrysoberyl mineral structure, which selectively absorb light wavelengths.
The Historic Discovery Site
The gemstone’s story begins in Imperial Russia, where the first significant deposits of Alexandrite were discovered in the Ural Mountains in the 1830s. Specifically, the material was found in emerald mines near the Tokovaya River, a region that quickly became the historical benchmark for quality. The initial discovery is frequently dated to 1834, coinciding with the coming of age of Alexander II, the future Czar, for whom the stone was subsequently named.
The original Russian Alexandrite is still revered as the finest quality material ever mined, setting the standard against which all other sources are measured. Its color change is typically the most vivid and complete, shifting cleanly from a perfect emerald green in daylight to a saturated ruby red under incandescent light. This intense color transition was particularly significant because the red and green shades mirrored the national military colors of Imperial Russia.
The Ural Mountain deposits were mined extensively throughout the 19th century, but they proved to be finite. Production began to decline dramatically toward the end of the century, and by the time of the Russian Revolution in 1917, the source was largely depleted. Natural Alexandrite from Russia is now extremely rare in the modern market, necessitating the discovery of new sources for the global gemstone trade.
Modern Primary Production Centers
The search for new deposits led to the establishment of two primary centers that currently supply the majority of the world’s Alexandrite. One of the most important modern discoveries occurred in the late 1980s in Brazil, specifically at the Hematita mine in Minas Gerais. This deposit revitalized the market, producing material that often exhibits excellent clarity and high-quality color change.
Brazilian Alexandrite typically displays a bluish-green or teal color in daylight, shifting to a purplish-red or raspberry-red under incandescent light. While these stones are often cleaner and possess fewer inclusions than those from other sources, the color change can sometimes be less saturated than the historic Russian gems. The Hematita mine is one of the few sources that has consistently yielded large, high-quality Alexandrite crystals, cementing Brazil’s status as a leading producer.
Sri Lanka, formerly Ceylon, has long been a major source, with Alexandrite often recovered from alluvial deposits alongside other gemstones. The Sri Lankan material is known for producing larger crystal sizes and superior transparency. However, the color shift in these gems is often softer, moving from an olive or yellowish-green in daylight to a brownish-red or purplish-red under artificial light. The distinct geological environments of these countries result in trace element variations, which account for the specific color characteristics unique to each location.
Emerging and Secondary Sources
Beyond the main producers, several other regions contribute smaller, more sporadic quantities of Alexandrite to the global market. These secondary sources often produce material that is highly variable in terms of color saturation and overall quality. Tanzania, with deposits in areas like Tunduru and Morogoro, has yielded fine-quality material since the early 2000s.
Tanzanian Alexandrite can sometimes display a color change comparable to the Brazilian stones, moving from a bluish-green to a strong red-purple. Madagascar has also emerged as a source, with its gems often showing a bright green daylight color that changes to a noticeable red or magenta. These African sources add important, though less consistent, material to the international supply.
India, primarily from the states of Andhra Pradesh and Orissa, also contributes Alexandrite, though the production is often of smaller size and variable quality. The Indian material frequently exhibits a greenish-gray daylight color that shifts to a brownish-red or purplish hue.