Chatoyance is a term used to describe certain gemstones where the appearance and colors shift as the angle of the light source or the viewing angle changes. It's also a good descriptive word that fits the way that light is reflected in some species of highly figured wood such as Odie's maple bowl.
Just what Wikipedia has to say.
In
gemology,
chatoyancy (
/ʃəˈtɔɪ.ənsi/ shə-TOY-ən-see), or
chatoyance or
cat's eye effect,
[1] is an
optical reflectance effect seen in certain
gemstones. Coined from the French "œil de chat", meaning "cat's eye", chatoyancy arises either from the fibrous structure of a material, as in
tiger's eye quartz, or from fibrous inclusions or cavities within the stone, as in cat's eye
chrysoberyl.
Chatoyancy in wood occurs in various species – particularly
hardwoods, and particularly where stresses from the weight of the growing tree result in denser patches, or where stresses cause
burl or
bird’s eye. This ‘figure’, which has a striking three-dimensional appearance, is highly prized by woodworkers and their clients alike, and is featured regularly in furniture, musical instruments, and other decorative wood products. Figuring takes on a variety of forms and is referred to as flame, ribbon, tiger stripe, quilting, among other names.
This effect is sometimes called wet look, since wetting wood with water often displays the chatoyancy, albeit only until the wood dries. Certain finishes cause the
chatoyancy (also referred to as wood iridescence,
moire, vibrancy, shimmer or glow) to become more pronounced. Oil finishes,
epoxy, and
shellac can strongly bring out the wet look effect.