Alexandrite is a rare and fascinating gemstone from the chrysoberyl family, known for its unique color-change effect. In daylight, it appears green to bluish-green, while under warm light it changes to red or purplish-red, often described as “emerald by day, ruby by night.” This effect is caused by the presence of chromium in its structure. It was first discovered in Russia’s Ural Mountains and named after Tsar Alexander II. Alexandrite forms under rare geological conditions, making it highly valuable and scarce. It has a hardness of 8.5, making it suitable for everyday jewelry. The gemstone also shows pleochroism, displaying different colors from different angles. Overall, Alexandrite is prized for its rarity, beauty, and association with balance and transformation.