Ever wonder how to identify real Turquoise, and distintuish it from imitations? Well here's some some useful information and tips on distinguishing between the varieties of genuine turquoise, and all the other stuff that's being sold as turquoise these days.
Natural turquoise is a hydrous aggregate of copper and aluminum. Turquoise gets its color from the amount of either copper or iron present. The really vivid blue turquoise is a result of high copper content, and the green tones come from higher iron content. Turquoise stones have varying degrees of matrix. True turquoise is opaque, with a waxy luster that may or may not include matrix.
The matrix refers to the vein-like inclusions that run through turquoise, so the matrix is basically some of the host stone where the turquoise has formed. Turquoise gemstone forms when water, that contains certain minerals and aluminum, leaks through rock, and is then being subjected to both heat and pressure. The turquoise stone will form as clumps or nuggets in the cracks of porous rock. Sometimes other gemstones such as chrysocolla will form together with the turquoise. Some people value the matrix in the turquoise, but others view the matrix as an imperfection and to them, it decreases the turquoise value.
The three main matrix colors are black, yellow and brown. A black matrix is the result of iron sulfide and this is typically the most favored matrix color. A yellow matrix is the result of rhyolite and the brown matrix comes from one or more of the sixteen types of iron oxide.
There are several types of "real" Turquoise
Often the turquoise stones will be enhanced. There are many different enhancements, and each treatment should be clearly identified. Turquoise can be dyed, stabilized or it can be sold as natural turquoise.
Natural & Stabilized Turquoise; Most turquoise sold for use in jewelry-making is stabilized. Stabilization increases the durability, hardness, chemical resistance and uniform appearance of the turquoise. Stabilization will usually darken the color and give the stone a glossy appearance. There are four main stabilization treatments currently applied to turquoise. The first type is a paraffin polish. The second is a polyresin polish. The third type of stabilization technique is where the turquoise is impregnated with a colorless bonding agent, commonly plastic. A fourth method, reserved for high-grade varieties of turquoise, is called the Zachery process, which does not use artificial additives such as plastic, and can only be detected at the molecular level. The time-consuming treatment results in a more dense stone that takes a better polish and is resistant to discoloration over time.
Reconstituted turquoise is made from ground-up turquoise such as pieces that are lost during the cutting process. There is usually very little natural stone in reconstituted turquoise, instead, it contains mostly resin and dyes. This is often called "block" turquoise and is considerably cheaper than other turquoise stones.
Dyed Turquoise: Turquoise is a porous material and easily accepts dye. The dye is used to modify the turquoise to a more marketable color. Dye can also be used to produce an outrageous color. Composite and reconstituted turquoise are the most commonly dyed materials. Dye can be used to color the turquoise or to color the polymer binding material. Sometimes black or brown dye is used to alter the color of matrix material to make it more obvious and uniform. Dyed turquoise is always worth less than untreated material of a similar color and quality.
Chalk turquoise is a porous white turquoise that is stabilized and dyed. It is typically dyed lively shades of blue, apple green, lime green, and fuchsia pink. This form of natural turquoise has a white chalk-like consistency and has the same chemical composition as turquoise with one exception: it does not contain copper--the element that causes the blue color of naturally occurring blue turquoise.
Affordable Turquoise Substitutes;
Howlite Turquoise; Howlite is found in the form of nodules that resemble cauliflower. Howlite can be dyed a stunning turquoise-blue, and has a naturally occuring matrix that looks very similar to natural turquoise. For these reasons, Howlite Turquoise is one of the most prominent turquoise substitutes, and probably the most difficult to tell apart from natural turquoise.
Turquoise Magnesite: Magnesite is a creamy, white stone that has a brown matrix, and is often dyed a beautiful shade of turquoise, as well as blue, green, orange, red, and other vibrant colors. Due to the inexpensive price of these dyed magnesite stones, they are one of the most popular and prominent turquoise substitutes on the market.
African Turquoise is actually a variety of dyed jasper, known in the industry as African ''turquoise'', that has an exotic blend of green base colors and dark matrix, making it an affordable, and very similar looking turquoise substitute.
Yellow ''turquoise'' has a subtle blend of gold, green, brown and black colors of quartz and jasper gemstones that are often found in the same mines as turquoise.
Mountain Jade; Turquoise-blue mountain "jade" is actually a high-grade, matrix-free, dolomite marble mined in Asia, which is dyed a wide variety of hues. The dye on mountain jade is usually only on the surface, so you can often see the original white color of the stone if you look in the drill hole, or even on the surface there can sometimes be small white patches. The same quality of matrix free turquoise, if it were real, would be one of the highest prices of natural turquoise.
Synthetic turquoise and turquoise simulants have been produced in Russia and China since the 1970s. Both countries are prolific producers. Synthetic turquoise is used to make cabochons, beads, small sculptures, and many other items. There are many different glass, plastic, and ceramic materials with an appearance similar to turquoise. Many of these can easily be distinguished from turquoise by testing their hardness, specific gravity, refractive index, or other properties.
How to tell fake turquoise from the real thing
It is difficult to tell the difference between a good fake and the real thing. However, there are a few tricks that can be used.
1. Look closely at the color and matrix. Turquoise has variations in color, however, dyed stones will have telltale lines, where the dye has collected in the natural cracks of the stone, or may be unnaturally uniform in color. Be cautious if you see turquoise with a wonderfully blue and very uniform color. The highest priced turquoise is generally the deep blue-green "robin's egg" or sky bule color, so if the price doesn't match the apparent quality, chances are it's not real.
2. Tap it on your teeth. Turquoise has a dull density when you tap it on your teeth. If the stone in question feels too much like plastic (a dull, soft feel) or glass (a sharp, dense feeling) to your teeth, be sure you know what you are buying. To learn the differences, get a piece of turquoise, a piece of amber, and a piece of quartz to tap. The amber will tap like plastic or resin. The quartz will tap more like glass.
3. Fake turquoise can easily be separated from real turquoise using a refractometer. A yellow, white, brown or green color should be an immediate clue that these might not be turquoise. An easy-to-do refractive index test will quickly separate all of these minerals from turquoise. Turquoise has a refractive index of 1.61 to 1.65.
3. Buy from reputable, knowledgeable suppliers. Most beads are manufactured (cut, polished, and drilled) in China, and travel through a variety of distribution channels on their way to the buyers. Due to language barriers and cultural differences, there are many difficulties to getting accurate information about the exact details of the stones. Trade names are commonly used which can be decieving, and misinformation is commonly spread through the supply chains, either intentionally or unintentionally.
Protecting Turquoise with Proper Cleaning
The color of turquoise can be altered by improper care and cleaning. If you own turquoise jewelry with a nice color, you should be careful about exposing it to prolonged sunlight, heat, cosmetics, perspiration, and body oil. If it has been exposed to cosmetics, perspiration or body oil simply clean it gently with a soft cloth that is wet with a very mild soap solution, followed by cleaning with a soft cloth that has been dampened with plain water. Then after the turquoise is dry, store it in a jewelry box away from bright light or heat.