Color Project No. 5 is Cobalt Violet. This is a Daniel Smith watercolor. I use this color a lot but never have I used it by itself and I love it. There is a good granulation but it can be a nice smooth gradation as well. It picks up easily if you make a mistake. I was thinking of something metallic as I painted this.
The metal cobalt was used in medieval stained glass for that bright blue, but they did not figure out how to make cobalt into a pigment for paint until 1802. By half a century later there was a range of colors that could be made with cobalt that are more lightfast than the similar hues made with dye. Do a google image search for cobalt pigments for the greens, blues and purples if you are color fiend like me who enjoys such things.