It happens to me all the time: A loved one hands me a velvet box. I open it and discover something dazzling inside, like a diamond-encrusted pendant featuring a sapphire the size of a chicken egg. I force a smile, but what I’m thinking is, “Sure it’s pretty, but what does it do?”

All right, the truth is that no one has ever given me a giant sapphire. It’s also true that most of us don’t expect our jewelry to be functional; we usually appreciate it for its beauty alone.

Sometimes, however, jewelry surprises and delights us by doing something more than simply being beautiful. An aunt of mine has a ring that was given to her by her father back in the early 1970s. She adores the ring, partly for the sentimental connection it holds, but also because its a show-stopper!

The ring was designed by Norman Teufel, and has two gold, diamond-studded hoops attached to the shank. The hoops spin independent of each other, and Teufel used tiny ball bearings so that they glide smoothly around their axis. Because the hoops are different sizes, and are each anchored at their corners, they have an undulating motion that makes them appear to dance.

It’s lovely. Take a look:

httpv://www.youtube.com/watch?v=r9oj0lyXRdA

More wonderful still: On the Teufel website, I learned that Teufel rhymes with joyful.

Jewelry that does something is fun! Imagine a ring with a tiny compartment for a lock of hair (or a dose of poison!) or a heart locket, for example.  And who doesn’t have a soft spot in their heart for a secret decoder ring?

My favorite piece of functional jewelry, however, is the wedding ring that conceptual artist Luke Jerram designed for his wife. It has a tiny glass lens, and is loaded with itty-bitty photographic slides of he and his wife together. If you hold the lens up to a candle flame or a small light, the images in the ring will project onto the wall, as a slideshow.

(Photo credit: www.lukejerram.com)

Now there’s a functional piece of jewelry! On top of being an impressive union of science and art, it serves the function of making Jerram Husband of the Year.

For those of us who are not Luke Jerram’s wife, I guess we’ll just have to be content with diamond-encrusted sapphires. (Chicken-egg sized please.)