A hard stone, such as the cat's-eye, which presents on a polished surface, and in the interior, an undulating or wavy light.
varying in color when seen in different lights or from different angles
"changeable taffeta"
"chatoyant (or shot) silk"
"a dragonfly hovered, vibrating and iridescent"
Having a certain optical reflectance effect, which can be likened to the sheen of a spool of silk.