Inside of this glass material prism is a text. The text needs to be white, but because it's inside the prism there's no light and it stays dark. I tried putting a light source in the prism and I tried to illuminate the text itself with a material. Neither of those seem to work.
I'm guessing you have scene wide Ambient Occlusion on (because the glass is black on the bottom where it touches the floor). Turn scene wide AO off and if you need AO on the floor just use AO in the diffuse channel of the floor's material ...or... leave scene wide AO on and add a compositing tag to the prism and uncheck 'Seen by AO'