While out clubbing in May 2007, Kate was seen wearing this costume jewelry bracelet.
The closeup shows us that this is a stretchy cuff-style bracelet that is divided into square sections. Each segment is connected to the others by stretch cords. The bracelet is primarily black with white polka dots arranged across it in a neat three row pattern, two dots per row. There are 6 white dots on each segment.
Here it is on Kate.
In the first full shot photo, you can see that her earrings are the ones written about here.