I think with most bead identification experience with color is very necessary. for example, I can spot most dyed coral by eye because I am very experienced with the color of natural coral. Though that is getting tough. This example is important regarding almost any historical bead, the chemicals used are different, and the colors of many reproduction beads are incorrect.

Price is also a huge indicator of quality, nice turquoise is expensive. though most consumers either do not know, or do not care about. Regarding turquoise, one of the most important attributes is hardness. Good quality turquoise is hard, and you can feel it when you handle it. Dense, hard turquoise will be warm to the touch under the intense hot lights of a dealers display case. In the same case lower quality turquoise will not be holding the heat because it is not as dense. In converse, high quality in normal ambient temperature will be cool to the touch, and less dense turquoise would be warm.

Stabilization is the coating of turquoise with wax, or some kind of spray on plastic stuff. Some people want their turquoise to be stabilized so as to insure that it will not change color from wear and skin oil. I do not think that stabilization is on its own a bad thing, I think of it as if you were to oil wood. The wood that is lacquered is still wood, it is just protected. It is good to know if your turquoise is stabilized. Though very excellent turquoise does not need protection because it is so hard. Any piece of turquoise can have different hardnesses and could change different colors within the same stone, that is the charm.