Hi Kelly and Amy! I have a piece I glass that used to be a shelf in my kids room. It's not clear but tinted grey. And then I just put a piece of white poster board under it and bent it up and behind the ornament in my light box. When I get home from work I will explain a bit further how I made my light box since there were some questions about it in the comments.
Canon 7D , Canon Rebel XSi. Lens: Tamron 28-75 2.8 / Canon 50mm 1.8 /Macro 90mm 2.8 / Canon 55-250mm 4.5 / PSE 8/ Lightroom 3