Polymer clay "turquoise" is a "genuine imitation" in the sense that the brilliant crafts persons who fabricate polymer clay "turquoise" fully acknowledge the materials they use. Indeed, they rightfully take great pride in the very close resemblance they can achieve!
So what is polymer clay? This is a synthetic material, not a natural clay. It consists of fine particles of polyvinyl chloride in a suspension material. It is pliable and can be sculpted into virtually any form. Polymer clay comes in a variety of ready made colors. The skilled polymer clay artist can mix their own colors as well.
Polymer clay turquoise is typically sold as "faux turquoise." Many artists strive to create a natural look, while others take a more abstract approach.
Several polymer clay artists have written on the techniques for creating realistic "turquoise," matrix and all, with this material. For an online demonstration of the project, go here!
The process has also been document in various books, including these:
Victoria Hughes. (2002). ArtRanch Techniques for Re-creating the Look and Ivory, Jade, Turquoise, and other Natural Materials. Iola, WI: KP Books.
Patricia Kimle. (2004). Polymer Clay Inspirations. North Light Books.