Chrysoberyl is a rare and sought-after mineral found in various parts of the world. The most important deposits are in regions such as Madagascar, Sri Lanka and Brazil. These areas are known for producing high-quality chrysoberyls in various color variations, which can range from greenish-yellow to red, blue and colorless.
The formation of chrysoberyl is usually tied to geological environments that have high temperatures and pressures. This mineral often forms in metamorphic rocks such as granulites and gneisses, where it is formed in the processes of metamorphism and rock transformation. It can also be found in pegmatites and alluvial deposits.

A notable feature of chrysoberyl is its ability to exhibit optical phenomena such as the cat's eye effect (chatoyance), which is primarily found in chrysoberyl from Sri Lanka. This creates a striking strip of light that travels across the surface of the stone, similar to a cat's eye (see video below). This optical feature makes chrysoberyl particularly sought after.
Alexandrite, a remarkable variety of chrysoberyl, is known for its unique color changing effect that varies depending on the light source and viewing environment. Under daylight or white light, Alexandrite displays a green color, while under artificial light, especially candlelight, it turns a reddish to purple color. This extraordinary optical property of alexandrite, also known as the alexandrite effect, is caused by the presence of trace elements such as chromium and iron in its crystal lattice.