Alexandrite cat’s eye is a unique and rare variety of the mineral chrysoberyl that displays a fascinating optical phenomenon known as chatoyancy or the cat’s eye effect. This remarkable gemstone exhibits a distinct band of light that resembles the slit-eye of a feline when viewed under a concentrated light source.
The primary feature of an alexandrite cat’s eye is its phenomenal color change. In daylight or fluorescent lighting, it typically appears as a greenish-blue or teal color. However, under incandescent light or candlelight, it undergoes a dramatic transformation and reveals shades of purplish-red or raspberry. This color change is caused by the gem’s ability to absorb certain wavelengths of light and transmit others, resulting in a striking visual effect.
The cat’s eye effect in alexandrite is attributed to the presence of inclusions called rutile needles. These parallel needle-like structures intersect with the gem’s fibrous crystal structure, creating a unique reflective effect. As light enters the stone, it is reflected off these inclusions, forming a single bright band of light that moves across the surface when the stone is rotated, reminiscent of a cat’s eye.
The color change and chatoyancy of alexandrite cat’s eye make it highly coveted among gemstone collectors and enthusiasts. Its rarity and exceptional beauty contribute to its value, making it one of the most sought-after and expensive gemstones in the world.
It is important to note that genuine alexandrite cat’s eye is quite rare, and there are synthetic and imitation versions available on the market. If you are interested in purchasing one, it is advisable to seek the assistance of a reputable gemologist or jeweler to ensure its authenticity.