Fake turquoise is almost indistinguishable from the real stone. One popular method of replicating turquoise is by dying howlite, a relatively inexpensive stone. Another method is by using colored plastics or ceramics. Imitation turquoise can look as good as the real thing and can be a perfectly good alternative to the real thing, but make sure you are paying the right price and getting authentic turquoise.
Hold the turquoise in your hand for about seven minutes. If it begins to warm, it is plastic.
Examine the turquoise closely. Real turquoise will have some natural color variation. This will be especially noticeable if you are examining turquoise beads. If they are real, they will all be slightly different shades.
Obtain a signed statement from the dealer that the stone is in fact real turquoise, specifying how it has been treated and from which mine it was extracted. Federal law requires all dealers to provide such a statement upon request.