Cat's Eye
The term cat's eye, or chatoyancy, is used to describe a phenomenal optical property in gemstones, in this case diopside. The effect, when present, appears as a bright, narrow slit similar to the pupils in the eyes of your favorite feline. This phenomenon is caused by parallel fibrous or needle-like inclusions that interfere with the passage of light through the crystal, scattering and reflecting light back to the viewer as a thin line.
Cat's Eye Classification
Common Name |
Cat's Eye |
Cat's Eye Optical Properties
Fluorescence |
SWUV: Inert LWUV: possibly green |
Pleochroism |
Dichroic, weak to strong light green or yellowish green and dark green |
Cat's Eye Characteristic Physical properties
Inclusions |
Black needle-like magnetite inclusions that might be magnetic, metallic like inclusions and liquid inclusions. |
Star
Star diopside exhibits the optical phenomenon called asterism, a star-like pattern created on the surface of a gemstone when light encounters parallel fibrous, or needle-like, inclusions within its crystal structure. Light that strikes the inclusions within the gem reflects off of the inclusions, creating a narrow band of light. When two or more intersecting bands appear, a star pattern is formed. Depending on the crystal, the star may have four, six, or even twelve rays. When only one band forms, it is classified as a "cat's eye."
Star Classification
Common Name |
Star |
Star Optical Properties
Refractive Index |
1.675-1.701 Tolerance:(+0.029/-1.701) |
Fluorescence |
SWUV: Inert LWUV: Inert |
Pleochroism |
Unobservable |
Star Characteristic Physical properties
Inclusions |
Black needle-like magnetite inclusions that might be magnetic, metallic like inclusions and liquid inclusions. |