Have you ever wondered where the term “jewel case”, referring to CD cases, actually comes from? I always assumed it had something to do with the shiny, transparent-as-crystal cases somehow reminding someone of a jewel. Nope, not even close.
The name is not derived in any way from containers for jewelry, or from the fact that the case is typically made from transparent plastic as is sometimes believed. Instead, the name originates from watchmakers’ use of the term jewel to refer generally to a polished hemispherical bearing used in a mechanism (high-quality mechanical watches and clocks commonly use gemstones, typically rubies, for such bearings because of their low friction properties). A jewel case has two molded hemispherical plastic bearings, in its hinges, hence the use of the term “jewel.”
Now you know.