@escapeartist said:
I put the diamond inside a cylinder, and then shrank the cylinder until the diamond's edge protruded a little outside of it.
I made a 32-sided polygon, 20' radius and Push/Pulled it up a foot. Deleted 30 sides. Turned the axes so one face was in the rg plane, laid guides and drew lines. Ditto the other face. Last, grouped and used a moving/copying rotate to finish the girdle. A neat, Sunday-afternoon modeling hack.
I'll be using this to decorate my UI in the other kind of ruby if I can ever finish fighting through the bugs.
http://www.MartinRinehart.com/models/graphics/sketchup_rubies_icon.gif
Now I've got a ruby, 40' around reduced to an 88x64 px icon.