Hi olenka and Capt. Riley. . .
What country are you in? . . . "polymer clays" are available all over the world, though not in some particular countries. It can always be mail ordered though (from several countries in Europe, New Zealand, Singapore, etc.)
Check out this page for more info:http://www.glassattic.com/polymer/supplysources.htm
("Clays" at top of page)
It sounds like what you have is one of the air-drying clays (those will shrink as they dry, and may take a day or more to dry thoroughly). Polymer clays will never "dry" ... instead they must be baked at around 275 degrees F in order to cure and harden them (usually done in an ordinary kitchen oven or toaster oven, though there are other ways).
Some of the brands of polymer clay are:
Fimo, Sculpey, Premo, Cernit, KatoPolyclay, DuKit, etc.
(each of those is a little different in consistency and characteristics, but are basically handled the same).
Check this page for finding out about polymer clays, the different brands, etc.http://www.glassattic.com/polymer/Characteristics.htm
Here are some suggesitons on baking polymer clays if you don't have an oven as well:http://www.glassattic.com/polymer/baking.htm
At Sarajane's website (www.polyclay.com
), most everything is made from polymer clay. She has written a couple of books as well. Sarajane often uses molds (which she's usually made with polymer clay as well) for making many of her objects and embellishments. Here's a page for lots of info on polymer clay and molds:http://www.glassattic.com/polymer/molds.htm
Capt. Riley, you asked about ways to make the henna marks without caning. There are various ways you could go about that if using polymer clay for the hand or other object.
...draw on the baked clay with a permanent pen (some will bleed a bit or turn purple over time though, like Sharpies) ...Pigma or Sakura Micron pens work well as will india ink, or just use watered down acrylic paint with a dip pen, etc.)
(...see more on this page: http://www.glassattic.com/polymer/letters_inks.htm
...use a stamp with pigment ink (or permanent ink?)...you can stamp the design after the clay is baked or before (if before, it may also be indented slightly)
(see more on this page: http://www.glassattic.com/polymer/stamping.htm
...carve (yikes!) or stamp into raw clay, then after baking fill the depressed areas with softened clay or acrylic paint (thick, tube types work best)...let set a minute or so... wipe off as much excess as possible with paper towels ... then wipe excess with water, or better, "sand" off the excess with 0000 steel wool, at least 400 grit wet-dry sandpaper with water, or even a dish scrubbie pad (if you want the surface to be shiny or a little shiny, buff the surface on your jeans or with an electric buffing wheel)http://www.glassattic.com/polymer/carving.htm
(look under "Backfill")http://www.glassattic.com/polymer/paints.htm
(look under "Antiquing")http://www.glassattic.com/polymer/sanding_tumbling.htmhttp://www.glassattic.com/polymer/buffing.htm
It's also possible to "carve" into baked or raw clay with a pin... then do one of the backfilling methods with something red.
...another possibility would be to "transfer" the image of a tatoo onto the clay (there are various ways to do that... see this page for more:http://www.glassattic.com/polymer/transfers.htm
(also, if you're interested in doing things without a pasta machine, you might want to check out this page:http://www.glassattic.com/polymer/pastamachines.htm
(under "No Pasta Machine?")