Pronunciation: [kˈats ˈa͡ɪ] (IPA) 
The spelling of the word "cats eye" can be a bit confusing. In fact, it is often misspelled as "cat's eye" with an apostrophe. However, the correct spelling is actually "cats eye" without an apostrophe. This is because "cats" in this case is being used as an adjective to describe the noun "eye." In IPA phonetic transcription, the word is /kæts aɪ/, with the "a" being pronounced as in "cat" and the "i" as in "eye."
A cat's eye refers to an optical effect found in certain minerals or gemstones that resemble the reflecting eyes of a feline. This phenomenon is most commonly observed in a gem called chrysoberyl, which exhibits a distinct band of light across its surface that simulates the appearance of a cat's pupil. This unique characteristic is further enhanced by the presence of parallel, needle-like inclusions found within the gemstone. The cat's eye effect, also known as chatoyancy, arises due to the reflection and concentration of light within the crystalline structure of the gem.
This chatoyant effect is highly praiseworthy, as it brings about an intriguing optical allure to the gemstone. In fact, it is considered one of the most desirable characteristics when evaluating the quality and value of a cat's eye gemstone. Typically, these gemstones are cut into smooth, cabochon shapes to maximize the display of the cat's eye effect.
The name "cat's eye" is derived from its visual resemblance to the slit pupils of a cat, which exhibit similar reflective qualities in low light conditions. Due to its captivating beauty and rarity, cat's eye gemstones are highly sought after by collectors and connoisseurs of fine jewelry. They are often used as centerpiece gems in rings, pendants, and bracelets, adding a touch of elegance and mystique to any piece of jewelry.
The word "cat's eye" derives from the resemblance of a certain type of gemstone to the eyes of a cat. The cat's eye gemstone is an optical reflector that displays a thin, single, vertical band of light when it is turned sideways. This effect is called chatoyancy, which comes from the French word "chatoyer", meaning "to shine like a cat's eyes". Over time, this term became associated with the gemstone and eventually expanded to refer to other objects, such as reflective road markers, that mimic the appearance of a cat's eye.
