Kate wore these on a night out in 2007.
Credit for the close up photo goes to My Small Obsessions.
These earrings are made of a large oval hoop strung with seven shimmery gold beads. The beads are graduated in size. They start out small and become enlarged as they lead to the center bead. Then the size reverses and the beads become smaller as they increase away from the center.
The hoop is attached to a French hook. It looks like this is gold plated, but I’m not too sure.
I found a similar looking pair on Amazon.com. They’re not an exact copy for Kate’s, though.