Stabilized – This is a natural turquoise usually in nugget form, but does not hold a luster. It is submerged into a stabilizing compound and dried, cut and prepared for jewelry. The turquoise has not been altered. The pores of the stone have been filled with a clear resin that makes the stone usable. This process allows for diversity of shapes and possibilities in jewelry making. Color Stabilized stones ARE altered and the color has been added by this process. This is not necessarily bad, but it has less value than a piece that is naturally colored.
Treated - This form of color enhancement has been used for thousands of years. It is done as discussed earlier by submerging into animal fat or vegetable oil and later air dried. This will not last very long.
Fake and Synthetic – Ceramics, bone, celluloid and plastic are used to imitate turquoise. Synthetic turquoise has a very natural matrix that is produced by placing stones in the synthetic “batter” .
A very common turquoise simulant is howlite. When dyed blue, with its marking, howlite is a dead ringer for some varities of turquoise.