The emission spectrum of quantum dots it proportional to the size of the particle. So the color can be “tuned” simply by sorting by mass. This has the practical application of making nice pictures for seminar talks.
upload.wikimedia.org/wikipedia/en/thumb/d/da/Kryptonite.JPG/443px-Kryptonite.JPG
Ejones ftw
In which a cat is the star of the show.
upload.wikimedia.org/wikipedia/en/thumb/d/da/Kryptonite.JPG/443px-Kryptonite.JPG
Ejones ftw