The hourglass symbol has signified many things through time. I have found it in Native American culture, Egyptian and even Free Masons. One of my favorites is the Lakota, a Native American tribe from the Black HIlls of South Dakota who believed there was a powerful connection between the sun and the Earth. They saw the design as an inverted triangle on top to symbolize the sky (sun or stars) as it touched the earth ... the bottom triangle being the earth.
The Lakota followed the path of the sun by the shadows through the seasons (their version of a sun dial). They were nomadic and didn't always camp in the same place, so the shadows marked time and told them when to migrate to another location.
Buffalo (an integral part of the culture) also had migratory patterns that coincided with the tribe's sacred sites. The Lakota painted star maps on hides, and believed buffalo embodied solar power; thus eating buffalo meat was eating energy from the sun.
While my bracelet here does not use colors that would have been typical to the Lakota (blue, white and brick red - the natural pigments of the time), the pattern embodies their sacred symbol and uses some interesting negative space. It is a pattern that Christine and I worked on using a design she created with a brick stitch, but I reversed the pattern to create the hourglass shape.