Turquoises are reasonably soft gemstones and thus quite sensitive. When turquoise is mined, a very low percentage of it is useable for turquoise jewelry.Since the colour may also fade out in the course of wearing.In fact, most of your turquoise bracelets and necklaces are either mined from that small percentage that has adequate hardness, or are enhanced.  Today even the top qualities receive a waxing and subsequent hardening treatment. 

Turquoises which have been sealed with artificial resin are also available in large amounts and at competitive prices. Their colour appears fresh, and they show a high resistance. But one should be careful, because many of these stones have been additionally dipped in colour before being sealed, and this colouring is a kind of treatment which must be indicated.

Generally,turquoise can exist in one of two forms. Natural or virgin turquoise has simply been shaped and polished, and has not been treated in any way. Natural turquoise is often the most desirable,it is very valuable.Treated turquoise has been changed through addition or processing.This procedure will make the sensitive gemstone sturdier.It is not considered as valuable as natural untreated product, and when cut it will not yield the natural turquoise inside. 

Among the ways of treating turquoise, treatments can include wax,staining, plastics impregnation, or colloidal silica deposition. These methods stabilize the turquoise, and when successful, they darken the color and fill in the pores in the stone. Stabilizing treatments can also increase stone hardness and therefore its shearing strength.However, the kind of treatment differs considerably. It makes sense, that naturally beautiful stones which have simple been waxed or hardened with artificial resin achieve higher prices and are more valuable than such stones, which have received colour-enhancement. 

While natural turquoise is often the most desirable, keep in mind that simply because turquoise is treated, it does not mean it is of lower quality. In fact, stabilized or treated turquoise can sometimes enhance the quality of each stone. Usually the color becomes more vibrant, and the stone reaches further hardness.

Wax, This processing will not be used to neither lower nor raise the quality of Turquoise. In fact, It is just to add a layer of colourless wax on the surface of the Turquoise so as to prevent the Turquoise from oils and other chemicals to some extent and to increase the fineness of the Turquoise.The waxed Turquoise which have excellent original colour and hardness,can reach the requirement of gem-grade. So this type of Turquoise are indeed natural ones which are very rare and rather expensive.
Plastics impregnation,or Hardness enhancement,Turquoises are reasonably soft and porous.Most of natural Turquoise is hard to cut and treat so that we can’t use them as gemstone. The plastics impregnation is to osmose the hot colourless plastics to Turquoises, thus filling the holes with it completely. After that, the hardness of the Turquoises can be raised so that it can be cut and polished. At present most of the Turquoise on the market have been treated in this way. Although we use this method to increase the hardness of the Turquoise, we won’t change the colour and the Matrix of the Turquoise,so the Turquoise treated in that way are relatively approved by consumers and Market.

Staining or Color enhancement,This type of turquoise called “chalk”is rather cheap.Chalk is the lowest of the Turquoises of the low grades.This Kind of Turquoise is so soft that if you would like to use it to make murals on the side walk, you could do it easily. In order to make chalk cut-able and usable, people can subject them to various chemical and hardening processes.Because this kind of Turquoie are processed by deep dyeing, we can’t tell the original shape of the treated Turquoise.Generally speaking, the staining process and plastics impregnation are operated on the Turquoise at the same time. After going through staining, the Turquoise chalk will look like natural Turquoise very much, but the value of the Turquoise can hardly equal the natural Turquosie. We would rather call them “plastics?than call them “the Turquoise?

How to indicate the Natural and Treated Turquoise?

General observation, which is the first step in testing any gem, reveals an unnatural color and usual luster not typical for better-quality untreated turquoise. The lower specific gravity would also indicate the turquoise might have been treated. To conclude that the turquoise has been wax-, paraffin-, or plastic-impregnated, a “hot point?is employed. It should be noted, however, that hot-point testing rarely works on plastic-impregnated stones and should be used with considerable caution when plastic treatment is suspected. A “hot point?can be an electrically heated point, such as a wax modeling tool, a soldering iron, or a red-hot needle. The “hot point?is brought close to, but does not touch, the surface of the turquoise. Easily seen under magnification, the wax or paraffin liquefies and flows ahead of the needle. To try to detect whether the turquoise has been treated with plastic, the “hot point?must come in contact with the surface of the stone in an inconspicuous spot. This test will leave a burn mark on the stone’s surface. In a positive test, the plastic emits an odor that is acrid, similar to burning plastic. It is important to remember that lack of a reaction does not necessarily mean that the stone has not been plastic-impregnated. It merely means that advanced testing using infrared spectroscopy is required.

You can also tell if you have a piece of stablized turquoise by looking at it under a loupe. By looking at a piece of turquoise under a loupe you will be able to see the pores of the stone.
Stabilized stone will look smooth and un-porous, and sometimes little gaps will be filled in with clear glass or quartz looking material. You must take into consideration though that some turquoise does contain quartz which takes an amazing polish with little effort. Some pieces, just being rubbed, will begin to polish. So remember that polish or deep color is not a full proof indicator of stabilization. A full proof way of ensuring that you have the product that you want be it stablized or natural is to have a turquoise dealer that you trust. Shop around and get to know who you are dealing with. When in doubt get samples and have them tested by a lab, that is a definite full proof way to prove what you are getting. 
Also ask questions from many people who buy turquoise, read books and get educated! Be a wise consumer and perhaps that will force those dishonest dealers to straighten up!

Valuable Turquoise jewellery should best be purchased from a jeweller you can trust.

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