A mineral, a gemstone that is a transparent and relatively rare and the most precious variety of Chrysoberyl. It changes color depending on the lighting: in daylight, it is green, while in artificial light, it takes on a red hue. This occurs due to the presence of chromium and iron in the crystals. It is often described as an emerald by day and a ruby by night. The most beautiful specimens deserve a diamond cut. The stone was named in honor of Tsar Alexander II. It is extremely expensive and almost always produced to order. In Russia, it is a symbol of sorrow and joy. In Europe – a symbol of romanticism and jealousy. In Sri Lanka, it symbolizes longevity and prosperity. It was believed that the stone calms the soul.