Look at these.
The file is in vector format so it does not need tracing. Downloaded can be found at this link http://www.minieco.co.uk/3d-paper-diamonds/
If you plan to cut the dashed lines select them first and and apply Extensions>Modify Path>Convert to Dashes. I found I had to remove a few dashed lines as they overlapped and would not have folded correctly.
Then again I think I will print and cut. I will print the dashed lines and cut the perimeter as I like the crisp look of folded lines.
If you have a look around the site there are other 3D items to download.