Fine Casting Plaster, more commonly known simply as Plaster of Paris is probably the most common general purpose plaster. It is a "beta" plaster versatile and economical it is used in numerous applications such as rubber moulds or hand / foot casting kits. It is light in weight and easily carved once set..

For harder plasters you may want to consider Herculite 2 or Crystacast which move up through the scales of hardness with Crystacast being the hardest used for the casting a creation of serious ornaments albeit at a price.