Alexandrite
The Rare Gemstone of Remarkable Colour Change.
Among the world’s most extraordinary gemstones, Alexandrite is celebrated for its exceptional rarity and captivating optical properties. Often described as “emerald by day, ruby by night,” alexandrite possesses the remarkable ability to change colour under different lighting conditions, making it one of the most sought-after gemstones in fine jewellery.
First discovered in the Ural Mountains of Russia during the 1830s, Alexandrite was named after the future Tsar Alexander II. Its striking colour transformation, combined with its royal heritage, quickly established the gemstone as a symbol of luxury and sophistication.
Scientifically, Alexandrite is a rare variety of the mineral chrysoberyl, with the chemical composition: BeAl_{2}O_{4}
The gemstone is composed primarily of beryllium, aluminium, and oxygen. However, what distinguishes alexandrite from ordinary chrysoberyl is the presence of trace amounts of chromium within its crystal structure. These chromium ions are responsible for the gem’s vivid colours and unique optical behaviour.
The phenomenon for which alexandrite is most renowned is known as the “Alexandrite effect.” This refers to the gemstone’s ability to appear in different colours depending on the source of light. In natural daylight or fluorescent lighting, Alexandrite typically displays shades of green, bluish-green, or teal. Under incandescent lighting or candlelight, the gemstone transforms into rich tones of purplish red, raspberry, or deep red.
This colour change occurs because alexandrite absorbs and reflects light differently across the visible spectrum. Daylight contains a higher concentration of blue and green wavelengths, while warmer artificial lighting contains more red wavelengths. The chromium within the gemstone selectively absorbs portions of yellow light, causing either green or red hues to dominate depending on the illumination. The human eye perceives this dramatic transition as a complete colour shift, giving alexandrite its almost magical appearance.
Although Russia was the original source of alexandrite, deposits have since been discovered in countries including Brazil, Sri Lanka, Tanzania, Madagascar, and India. Nevertheless, fine Russian alexandrites remain particularly prized for their intense and distinctive colour changes.
Pricing for alexandrite varies widely across the collection, with pulled Czochralski stones typically in the £50–£150 range, while natural colour-change, certificated alexandrites range from under £1,000 to over £10,000 for larger, higher-quality examples.
Beyond its beauty, alexandrite is also admired for its durability. Ranking 8.5 on the Mohs hardness scale, it is well suited for use in rings, pendants, and other fine jewellery intended for regular wear. Within the world of bespoke design and luxury jewellery in London, Alexandrite is often chosen for its individuality—favoured in pieces where subtle rarity matters more than overt brilliance.
Combining scientific intrigue with exceptional beauty, alexandrite remains one of nature’s most fascinating gemstones. Its rare ability to transform colour under changing light continues to captivate gem enthusiasts, collectors, and jewellers across the world, securing its place as one of the most remarkable gemstones ever discovered.
In the world of luxury jewellery in London, alexandrite has become a gemstone of quiet distinction, often chosen for bespoke pieces that favour rarity over statement. Today, it is also increasingly appreciated in luxury jewellery in NYC, where collectors and designers alike are drawn to its rare optical drama and understated prestige.
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