Alexandrite is a rare variety of chrysoberyl distinguished by its pronounced color-change phenomenon, typically shifting from green or bluish-green in daylight to purplish-red or reddish hues under incandescent light. This optical behavior is caused by selective absorption of light related to chromium trace elements within the crystal structure and places alexandrite among the most scientifically studied color-change gemstones within gemology. Detailed gemological classification and reference information on color-change gemstones can be found in the Gemstone Encyclopedia.
Natural alexandrite is primarily associated with historically significant deposits in the Ural Mountains of Russia, while additional natural sources include Sri Lanka, Brazil, and parts of East Africa. Stones from different origins may exhibit variations in saturation, hue balance, and intensity of color change. The role of geographic origin, together with rarity and supply limitations, is further examined in the context of gemstone origin and scarcity within the Gemstone Guides.
Quality evaluation of alexandrite is based on several core criteria: the strength and completeness of the color-change effect, the quality of hues under both lighting conditions, transparency, and clarity. Unlike many colored gemstones, size alone is not a primary determinant of value. Fine-quality natural alexandrites above one carat are statistically uncommon, a factor frequently discussed in relation to rarity and long-term value formation in the Investment Insights.
Independent gemological certification plays a central role in the alexandrite market. Certification confirms natural origin, documents color-change behavior, and distinguishes natural stones from synthetic or laboratory-grown materials. An overview of trusted gemological laboratories and certification standards is provided in the Gemstone Guides – Gemological Laboratory, along with guidance on interpreting laboratory reports.
With a Mohs hardness of 8.5, alexandrite is suitable for use in fine and bespoke jewelry when durability considerations are respected. However, due to its scarcity and gemological significance, it is more commonly positioned as a collector gemstone or a component of investment-oriented portfolios rather than mass-market jewelry production. Practical considerations for selecting gemstones for jewelry applications are outlined in the Jewelry & Gold Guide.
