Silver tie clip with a brass shell casings.
The 9mm is available with a primer in Sterling silver or Swavorski crystals in diamond, ruby or sapphire color.  
The 45 Cal is only available with the primer in silver or diamond.  
Shown here with the silver primer.
Click on the alternative views to see center/primer options.  If you are buying for a man and you are not sure about the color, I recommend the silver center because this looks the most like a real shell.