The Collaborative International Dictionary of English v.0.48:

Chatoyant \Cha*toy"ant\, a. [F., p. pr. of chatoyer to be
   chatoyant, fr. chat cat.] (Min.)
   Having a changeable, varying luster, or color, like that of a
   changeable silk, or oa a cat's eye in the dark.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Chatoyant \Cha*toy"ant\, n. (Min.)
   A hard stone, as the cat's-eye, which presents on a polished
   surface, and in the interior, an undulating or wary light.
   [1913 Webster]

WordNet (r) 3.0 (2006):

chatoyant
    adj 1: varying in color when seen in different lights or from
           different angles; "changeable taffeta"; "chatoyant (or
           shot) silk"; "a dragonfly hovered, vibrating and
           iridescent" [syn: changeable, chatoyant,
           iridescent, shot]