A "mystery clock" on display as part of the "Jazz Age" exhibit at the Cleveland Museum of Art in Cleveland, Ohio, in the United States.

A "mystery clock" is a timepiece whose hands appear to "float". Such timepieces were fashionable between 1900 and 1940.

This clock was made about 1921 by Cartier, a French jewelry firm established in Paris by Louis-François Cartier (1819–1904) in 1847. In 1916, his grandson, Jacques Cartier, emigrated to the United States and opened a New York City branch of the business on Fifth Avenue.

The actual designer of this timepiece is not known. The creator of the movement is not known. The piece itself is made of gold, platinum, ebonite, citrine, diamonds, and enamel. Ebonite (or Vulcanite) is a very hard artificial resin created by Charles Goodyear in 1844. Citrine is a yellow to brownish-red variety of quartz (the second-most used quartz gemstone after amethyst).

This clock was first owned by Anna Thompson Dodge, wife of automobile manufacturer Horace Dodge.

1. CMAJazzAge