Compare this video (Gemesis diamonds) to http://www.youtube.com/watch?v=021v4B... (Apollo diamonds, 2 parts). Different techniques, different results. Gemesis diamonds are mostly yellow due to the Nitrogen in the atmosphere getting inside the crystal during the growing process. Apollo diamonds can be created in all colors including colorless depending on how much impurity is introduced in the growing chamber. e.g. add boron to make blue diamonds.
Discovery Communications own the copyright of this clip from the "How do they do it" TV show. Show your support by subscribing to Discover Channel, Science Channel and TLC. They are my favorite channels and my reason to subscribe to cable TV.