Since, as we all know, google is your friend, I went on a search to see what I could learn. It appears this is a fast growing and very popular technique for both jewelry and other figural types of collectibles. So popular, that youTube has several videos about the subject. The video that I have attached to this blog show how the old technique of millefiore is the basis of polymer, but the material has changed from glass to polymer. To me, some of the pieces also have the look of Venetian glass, such as this stunning bracelet shown here. The colors in it are just fabulous.
Photo credit natakorneeva
According to wikipedia, Polymer clay is a sculptable material based on the polymer polyvinyl chloride (PVC). It usually contains no clay minerals, and is only called "clay" because its texture and working properties resemble those of mineral clay. It is sold in craft, hobby, and art stores, and is used by artists, hobbyists, and children.
Because of the material, designs tend to be very colorful and bright. There is a fabulous blog about Polymer clay jewelry done by Russian artist Natakorneeva. The blog is in Russian, so I cannot read it, but it is a cornucopia of delightful polymer clay jewelry products with picture after picture of finished products.
For those who would like a bit more info, here is the youTube video that I promised. It is a good overview and gives history and design techniques. Grab a cup of coffee and enjoy!