The Geology Museum displayed this 6.2-carat fancy yellow diamond at its open house Sept. 10. A diamond’s color is classified by a letter grade, ranging on a scale from D, which is totally colorless to Z, which is a pale yellow or brown color. Diamonds with more depth of color than Z color fall into the fancy color diamond range. ‘The fact that anyone is willing to give us a 6.2-carat diamond these days is great. People love it because it’s so colorful, and with the LED lights, it looks like it’s on fire,’ said Bruce Geller, director of the Geology Museum.