Learn the difference between real turquoise and imitation turquoise. Natural turquoise, an aggregate of copper aluminum phosphate hydrate, formed under heat and pressure, is often soft or porous when mined. The various colors found in turquoise result from the presence of either copper or iron--vivid blue is from copper and the softer green tones from iron. Turquoise stones can also have patterns of brown, yellow ochre and black matrix, produced from copper compounds. True turquoise has an opaque, waxy luster that may or may not include matrix, depending on the type of turquoise.
Understand that the gemstones used in almost all turquoise jewelry must be stabilized because natural turquoise is usually too soft to be worn as jewelry. The stabilization process of a turquoise stone involves submerging it into a stabilizing compound. This results in the natural action of the stones’ capillaries drawing the stabilizing compound into the gemstone.
Get familiar with the enhancements that are applied to turquoise stones. The American Gem Trade Association (AGTA) outlines the different enhancements that are applied to turquoise stones. These various treatments should be clearly identified by the seller.
Learn to identify turquoise by where it was mined. Turquoise mines are located all over the world, and each mine produces stones that have distinctive colors and markings. Sleeping Beauty turquoise is mined in Arizona. It is a solid stone (no matrix) and it ranges in color from royal blue to a light sky blue. Chalk turquoise is mined in China. It is white and porous, so it must be stabilized and dyed. Chalk turquoise is dyed in various hues of blue and green because the mines don’t contain copper, which is the element that naturally gives turquoise its distinctive hue. Chalk turquoise almost always has a matrix pattern, which resembles faint cracks. Persian turquoise is mined in Iran. This stone is known for its extremely vibrant, robin’s egg blue color. Persian Turquoise" does not have a matrix, and some people refer to any turquoise stone does not have the black or brown veining commonly found in turquoise mined in the United States as “Persian Turquoise.” The main thing to look for, other than a lack of a matrix, is the distinct, bright blue color. Bisbee turquoise is mined in Bisbee, Arizona. The Bisbee mine produces turquoise stones in many different shades of blue and the stones have a reddish-brown matrix. This pattern is only found on the stones taken from the Bisbee mine.
Buy from a reputable jeweler. Turquoise has a wide range of values, depending on which mine it came from. The price can also depend on demand and scarcity (some mines are nearly depleted.) Be sure to buy your turquoise from a jeweler that is a member of AGTA. If you want to be sure you are buying authentic Native American turquoise, make sure the dealer is a member of the Indian Arts and Crafts Association (IACA).
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