Woodworking word of the day: chatoyance

What is chatoyance? I read the word in a finishing article online, but my dictionary isn't much help.
—Kent Farthing, Madison, Wis.

Borrowed from gemology, chatoyance describes the color-changing properties of some woods, Kent. When the wood cells in a tree grow in nonuniform directions, light often reflects off the cells at slightly different angles. So a piece of wood can appear to be one color when viewed from one direction, but will change colors when rotated. The color changes may present as an undulating motion as you turn the wood, especially in figured wood, such as the curly maple tabletop shown above.

Dyes enhance chatoyance, penetrating deeply into the cell structure and lending an otherwise flat piece a 3D effect.