Alexandrite is a gemstone variety of the mineral chrysoberyl. It is renowned for its color-changing property, which shifts from green in daylight or fluorescent light to red or purplish-red under incandescent light. There are no specific “types” of Alexandrite crystals, as the crystal structure is the same across all specimens. However, the color and quality of Alexandrite can vary, which can make each crystal unique. The value and desirability of Alexandrite are determined by factors such as color saturation, hue, and strength of the color change. The following are some terms that are used to describe Alexandrite based on its color and quality: 1. Fine Alexandrite: These are considered the highest-quality Alexandrites with a vivid and intense color change from green to red or purplish-red. They exhibit excellent transparency and strong color saturation. 2. Cat’s Eye Alexandrite: This variety displays the phenomenon known as chatoyancy, giving the appearance of a narrow, bright band of light across the surface that moves as the gemstone is rotated. This is caused by needle-like inclusions reflecting light. 3. Alexandrite Chrysoberyl: This refers to the mineral itself, chrysoberyl, which can exhibit Alexandrite-like color change properties. However, to be considered true Alexandrite, the color change must be distinct and dramatic. 4. Translucent Alexandrite: Sometimes, Alexandrite crystals can have a translucent or slightly included appearance. While they may lack the transparency of higher-quality specimens, they can still exhibit a remarkable color change. It’s important to note that Alexandrite is a relatively rare and valuable gemstone. Synthetic or lab-grown Alexandrite also exists, which can offer more affordable options, but genuine, natural Alexandrite is highly sought after by collectors and gem enthusiasts.