Millefiori is Italian for "Thousand Flowers."  Originally a technique used for making decorative glass works, a similar process can be used to make designs in polymer clays, such as Fimo and Sculpey.  These materials are perfect for beads, earrings and other jewelry.
 For this flower, I've chosen a green center with blue petals on a white background.  It's a good idea to pick a high-contrast background or it will be hard to see the boundaries of the petals.
 A good craft store will have a lot of different shades to choose from.  I prefer to buy primary shades and lots of black and white and mix my own.  That provides a smoother color gradient and greater control over the end result.  Also, it's way cheaper that way, and mixing the colors gets the clay worked to a usable consistency.