I get asked this a lot.  Polymer clay is actually not a natural clay but is a modeling material that is made from polymers, resins, coloring agents, plastic, and a polyvinyl chloride (PVC) base.  It is really easy to work with and hardens only when it is baked.  It cures at between 230 F and 300 F, depending on the brand that you are using.  The only special equipment you need is an oven (your home oven or a toaster oven will do),  pans to bake the clay in that you won’t be using for food stuff  a thermometer to make sure the oven maintains the correct temperature, and what ever else you can think of that you would like to try!  There is no proof that polymer clay is dangerous to eat but I use separate pans to bake it in because why risk it.  (I do reuse the foil pans that you can buy in the grocery store, as they don’t cost a lot of money and are easy to find.)

There are many brands of polymer clay, each with their own color palette and other characteristics.  They can also be combined with each other with very few concerns.  You can also add alcohol inks, acrylic paints, embossing powders, metal leaf, glitter, spices and what ever to the color to change color and texture.  You can do this with no worry as long as what you are adding can safely be baked at the temperature that polymer clay is.

If you want to get started with polymer clay, I would visit the library and check out a book or two, and read a little about it.  Then I would visit your local craft store and buy a block or two of polymer clay.  Then play with it , have fun and see how easy it is to work with and go from there.  That is what I did and I became an addict!  It is now my favorite medium to work with.