A series of Emerald themes, based on the vrunner engine. They are based off the default theme, and are all visually reminiscent of precious stones or precious metals.
You must have Compiz 0.9 as your default WM. (They might work on 0.8, but this is untested.) You will need Emerald as your window decorator. Double-click on the downloaded files to add them to Emerald Theme Manager. Then switch between themes by clicking on them.