Definition

Noun: 1. A type of gemstone: A "cat's eye" is any of several gemstones that, when cut and polished into a rounded, cabochon shape, display a narrow, bright band of reflected light that moves across the surface. This optical effect, called chatoyancy, resembles the slit pupil of a cat's eye.

Usage

• The term is used to describe the gemstone itself, focusing on its distinctive visual property.
• It is most commonly associated with chrysoberyl cat's eye, which is often simply called "cat's eye" in gemology. Other minerals like quartz or tourmaline can also exhibit this effect.

Examples

Advanced Usage

• "Cat's eye effect": This phrase is used to describe the chatoyancy phenomenon itself, not just the gem.
  • The fibrous structure of the mineral is responsible for the cat's eye effect.

Variants and Related Words

• Chatoyancy (n): The technical optical phenomenon exhibited by cat's eye gems and some woods, characterized by a band of reflected light.
• Cabochon (n): A gemstone that is polished but not faceted, typically with a convex, rounded surface. This is the standard cut for displaying cat's eye effects.
• Tiger's eye (n): A related chatoyant gemstone, a form of quartz that displays a silky, golden-brown banding.

Synonyms

• Chatoyant gem: A more technical term for a gem displaying the cat's eye effect.

Notes on Different Meanings

• The primary and most specific meaning of "cat's eye" in this context is the gemstone. It should not be confused with other uses, such as:
  • The reflective road stud used for lane markings (a separate compound term: "cat's-eye reflector").
  • The eye of an actual cat. This explanation covers only the gemological definition.

Noun

1. any of various gems (as chrysoberyl or chalcedony) that reflect light when cut in a rounded shape