There are five “kinds” of turquoise as described by law:

Natural turquoise - turquoise that is so hard and beautiful that it is simply mined, cut, polished and set into a piece of jewelry or carved into a fetish or sculpture. Less than 3% of all the turquoise on the market worldwide is natural.

Stabilized turquoise - soft or "chalk" turquoise has been infused with a clear epoxy resin. The resin, under pressure, absorbs into the rock, which permanently hardens the rock and deepens the color. (Kind of like the way a sponge turns a deeper color when you get it wet.) Unlike the collectible natural turquoise which deepens in color over time by gradually absorbing oils from the skin as it is worn, the colors in stabilized turquoise are permanent. Most of the turquoise on the market is stabilized and should not cost as much as natural. Stabilized turquoise can be very beautiful, and is a good buy. (More than 97% of the turquoise on the market is stabilized.)

Treated turquoise - soft or "chalk" turquoise that is stabilized as described above, except that the epoxy resin is also dyed. Colors in treated turquoise have a tendency to look artificial. Prices should be much less than natural or stabilized.

Reconstituted turquoise - turquoise "chalk" that is very low grade and has been ground into powder, saturated with epoxy resin, dyed, and compressed into blocks or cakes to be cut into shapes for jewelry making. Prices should be most inexpensive.

Imitation turquoise - there is no turquoise in this category. Either there are stones like Howlite (white stone, very porous) dyed to look like turquoise or there is pure plastic (epoxy resin) that has been dyed to look like turquoise. It is a shame that these materials are set in silver and priced as if they had intrinsic value.

Unfortunately, treated, reconstituted and imitation turquoise can be made to look remarkably like collectible stones. Trust is the bottom line. Be sure that the seller guarantees that the jewelry is what he or she says it is, not just verbally, but in writing, including a signature on the sales document with the name of the store on it. Also be sure to shop at businesses that offer refunds, whether the item was bought on sale or not.

Source: Indian Arts and Crafts Association, 4010 Carlisle Blvd. NE, Albuquerque, NM 87107