Frequently customers ask if the turquoise in our store is “real.” The answer is yes. We always make sure to ask where it is from, where the artist got it, compare it to our knowledge of what it should look like, etc. Over the years, the artists we represent know to include that information when they bring in new jewelry.
It is a valid question, after many resourceful people have fraudulently sold other minerals to the unsuspecting customer as being turquoise. It is getting exceedingly difficult to discern some of the fake from real on today’s market. White Howlite and Magnesite that have been dyed blue are widely used in the fake turquoisemarket. It is wise to purchase from galleries and shops you trust who have years of experience in developing the eye and knowledge to know the difference.
Turquoise is an opaque, blue-to-green mineral that is a hydrated phosphate of copper and aluminium, with the chemical formula CuAl6(PO4)4(OH)8·4H2O. The finest of turquoise, or slightly more than window glass, reaches a peak Mohs hardness of just under 6.
It is rare and valuable in higher grades and has been prized as a gemstone and ornamental stone for thousands of years owing to its unique hue.In many cultures of the Old and New Worlds, this gemstone has been esteemed for thousands of years as a holy stone, a bringer of good fortune, a show of wealth, or a talisman.Turquoise is most commonly set in gold throughout the world, with the exception being the Southwestern US, where it is most commonly set in silver. North American Turquoise is some of the most envied in the world for its beautiful color matrix and high-grade quality.
Color: The word turquoise comes from the French for “Turkish”, as the gem was originally imported from Turkey.
Hardness and richness of color are two of the major factors in determining the value of turquoise; while color is a matter of individual taste.
The colors of turquoise cover a far wider range than most people think. Colors often vary considerably within various locations at the same mine. Some mines have both green and blue shades in them. If the deposit has more copper, the turquoise will be in the blue range; if the deposit has iron in it, then the stones will look greener; if more aluminum than normal is present, the stones are in the green to white range. The addition of zinc yields a brighter yellow-green color and adds hardness to the stone. The state of Nevada produces some unique shades of bright mint to apple to neon yellow green that are unequalled anywhere else on earth. Some of this unusual turquoise may contain significant zinc and iron, which is the cause of the beautiful bright green to yellow-green shades. Significant quantities of the mint to yellow-green colors have so far been found in Lander County, specifically in the Carico Lake district, the Pixie mine at Cortez and at Damele and Orvil Jack mines. In some cases, stones from one mine resemble very closely those from another mine and can be virtually impossible for even a gemstone expert to tell the difference. No one can say that stones from a certain mine are all one color, as there is always some amount of variation, but in general the bulk of a mine’s production shares some common characteristics. Turquoise can also come in varying grades, with the higher quality generally being darker in color, harder and with very little porosity. Often the stones of a lighter color have a tendency to be softer and more porous, and this may give them the potential to change color with wear – however this is not always the case.
There is a lot of confusion related to white stones used in Native American jewelry. White Buffalo is a stone frequently and erroneously called white turquoise. It’s a white stone surrounded by black and brown flint-like chert (an opaque variety of quartz), which creates beautiful patterns. The stone appears in veins, is as hard as turquoise (Mohs hardnessscale of 5.5 to 7.5) and cuts and polishes like turquoise, but is not turquoise. Howlite is also quite frequently sold in its natural form with misleading names like “white turquoise”, “white buffalo turquoise” or “white buffalo stone”.
A reputable lab took material sold as “white turquoise,” used x-ray diffraction, and learned that it was a combination of magnesite and dolomite. Others report that material sold as whiteturquoise is howlite or opalized calcite. So, much of the material being sold as “white turquoise” or “white buffalo turquoise” would be better if it was called “white buffalo stone” because it is not turquoise. Don’t be misled by the fashion industry and less reputable industry dealers misnaming stones to make a profit!Turquoise can change color, caused by light, or chemical reactions from cosmetics, dust or the acidity of the skin. A pale blue color can change to a dark green over years of wear….thus the old term “greasy green”.
Natural turquoise: This means a stone has had no alteration to its composition. It is usually a fine gem quality turquoise that is harder and more durable than other softer, stabilized, or synthetic types. All other factors being equal, untreated turquoise will always command a higher price.
Treatments: Turquoise is treated to enhance both its color and durability (increased hardness and decreased porosity).
Historically, light waxing and oiling were the first treatments used in ancient times, thereby enhancing the color and luster. Oiled and waxed stones are prone to “sweating” under even gentle heat or if exposed to too much sun, and they may develop a white surface film or bloom over time.
Enhanced turquoise is turquoise that has been treated to enhance color and resist wear and tear. Through the enhancement process, turquoise is infused with vaporized quartz, resulting in a harder, more uniform-looking stones. Enhanced turquoise is considered the closest on the spectrum of treated turquoise to high-grade turquoise.
This process consists of pressure impregnation of otherwise unusable chalky stone by epoxy and plastics (such as polystyrene) and water glass (sodium silicate) improve durability. Turquoise that is softer, porous and chalky and will not hold together by itself. Treating the stone in this way makes it darker and harder, and less likely to fall apart or crack when worked. To complicate the subject even further, there is high-quality turquoise that is stabilized due to the seam-structure in the stone that might fracture if not treated. This turquoise is too hard to absorb the plastic and most of it settles in the matrix cracks to provide stabilization.
The epoxy binding technique was first developed in the 1950s and has been attributed to Colbaugh Processing of Arizona, a company that still operates today. The majority of American material is now treated in this manner although it is a costly process requiring many months to complete.
The use of Prussian blue and other dyes (often in conjunction with bonding treatments) to “enhance” its appearance, make uniform or completely change the color, is regarded as fraudulent by some, especially since some dyes may fade or rub off on the wearer. Dyes have also been used to darken the veins of turquoise.
Perhaps the most extreme of treatments is “reconstitution”, wherein fragments of fine turquoise material, too small to be used individually, are powdered and then bonded with resin to form a solid mass. Very often the material sold as “reconstituted turquoise” is artificial, with little or no natural stone, made entirely from resins and dyes. In the trade reconstituted turquoise is often called “block turquoise” or simply “block”.
Since turquoise is often found as thin seams, it may be adhered to a base of stronger material for reinforcement. These stones are termed “backed,” and it is standard practice that all turquoise in the Southwestern United States is backed. Native Americans of this region, because of their heavy wearing of turquoise, discovered early on that backing increases the durability of thinly cut slabs and cabochons of turquoise. Early backing materials included the casings of old model T batteries, old phonograph records, and more recently epoxy steel resins. Backing does not diminish the value of turquoise, and actually the process is expected for most domestic American turquoise.
The mother rock or matrix in which turquoise is found can often be seen as splotches or a network of brown or black veins running through the stone in a netted pattern. While this does not devalue the stone and in some cases even enhances the value, generally it is not highly appreciated in the Near East where unblemished and vein-free material is ideal.
Care of Turquoise: Being a phosphate mineral, turquoise is fragile and sensitive to solvents; perfume and other cosmetics will attack the finish and may alter the color of turquoise gems, as will skin oils, as will most commercial jewelry cleaning fluids. Care should be taken when wearing turquoise: cosmetics, including sunscreen and hair spray, should be applied before putting it on. Never wear it in a hot tub or swimming pool where harsh chemicals will alter the appearance. It is also advised to not put it in an untrasonic cleaner.