Usually referred to as "Emerald by day, Ruby by night," Alexandrites are indeed precious and prized possessions in our industry.The most extraordinary characteristic of Alexandrite is its phenomenal color change. This gemstone displays a distinct shift from green-blue in daylight to purplish-red under incandescent light. This optical phenomenon, known as the "Alexandrite Effect," is due to the complex way in which the gemstone's crystal structure absorbs and reflects light.