weird dots when using a gem

hey,

im building a car for a school project but i want it to have a roof which generates solarpower.

So what i did was, i took a sapphire and put that as roof instead of paint -> car -> black.

Then i started rendering and look what the results are:

https://fbcdn-sphotos-c-a.akamaihd.net/hphotos-ak-ash3/860022_10200267567644926_626634584_o.jpg that also happens in other situations. Adjusting the render quality, background, or resolution doesnt affect this. How to fix it?

SolidworksPhotoview 360