Chatoyant
Chatoyant , adjective
[French, present participle of chatoyer to be chatoyant, from chat cat.]
(Mineralogy) Having a changeable, varying luster, or color, like that of a changeable silk, or oa a cat's eye in the dark.
Chatoyant , noun
(Mineralogy) A hard stone, as the cat's-eye, which presents on a polished surface, and in the interior, an undulating or wary light.