Just by looking at given photo, you can tell that it's a silicon diode, probably with a part number of D5, which is a center tapped diode. You can substitute that SMD part with any silicon diode of the same or greater current rating.

It says DG, then a space, and then a horizontally flipped C (in this exact orientation)

Thanks to both, will this component alone prevent the card from even post? When I got the card I tested it in varius motherboards and it didn't post in any, so I started looking at the card closer and its the only component missing.