An article by Lee Anderson
This article discusses various types of turquoise as they relate to the jewelry industry.
This turquoise comes directly from the mine. It is cut, shaped, polished, and set into jewelry. Perhaps it had only been drilled, polished, and suspended on a necklace. In any event, the stone has had no man-made treatment or additives other than the polishing compounds to set off its luster. Most stones used in their natural state are very good to gem quality — in other words, hard and dense, with an inherent luster that does not lessen as it is exposed to its natural setting.
This is a natural turquoise, usually in nugget form, that is too porous or soft to hold a luster. It is therefore submerged into a stabilizing compound, frequently an epoxy resin. The natural capillary action of the porous stone draws this stabilizing compound throughout the stone. It is then dried. When thoroughly dried, it can be cut, drilled, cabbed, etc., and prepared for jewelry. Please note that the turquoise has not been altered; rather, the pores of the stone have been filled with a clear resin that makes the stone usable. If this type of turquoise were not on the market, many, many, jewelry artisans would be unemployed. It allows wide diversity. For example, necklaces of tiny turquoise beads now can be made and tiny inlay is possible. Colors will not change because the pores are sealed. It is not practical to use a high-grade natural stone for heishe; too much turquoise is wasted in the grinding, and the resultant bead will be fragile and eventually change color.
On the other hand, some stabilizing compounds can have color added. This causes the turquoise to assume a color that is not naturally inherent to that stone. This is referred to as “color shot” or “color stabilized,” a misleading term that implies the natural color is “stabilized.” This, of course, is not true; color has been added. This practice is not necessarily bad. Jewelry-making is an art, and this color enhancement can improve the appearance of the piece. It goes without saying that the value is less than that of naturally colored turquoise.
This form of color enhancement has existed for thousands of years. Pogue discusses writings on this subject that pre-date Christ. A common treatment is to submerge the stone in animal or vegetable oil and later air-dry it to give it a luster that did not previously exist. Unfortunately, this luster will not last long, and wearing the piece will likely leave oil stains. Many sellers have had to leave the area shortly after making such a sale! Even today, some turquoise merchants submerge the stone in water to enhance its color and weight.
Fake and Synthetic
People have been faking turquoise for centuries using ceramics, bone, color-enhanced minerals, and more recently, celluloid and plastic, among other things. This “fake” turquoise not much of a problem now, as people are simply too familiar with turquoise. However, “synthetic” turquoise, frequently chemically perfect, has appeared on the market in some quantity. This is literally stove-top turquoise. It has a very natural matrix created by placing stones in the “batter” or sprinkling in pyrite, etc. When the mix is cut, then cabbed, these foreign additives, which are real, add to the illusion that the entire stone is natural. Synthetics become fake if not properly identified
References / Recommended Readings
John Adair, The Navajo and Pueblo Silversmiths, University of Oklahoma Press, 1944.
Margery Bedinger, Indian Silver, Navajo and Pueblo Jewelers, University of New Mexico Press, 1973.
M.G. Brown, Blue Gold, The Turquoise Story, Main Street Press, Anaheim, CA, 1975.
Larry Frank, Indian Silver Jewelry of the Southwest, Schiffer Publishing Ltd., Westchester, Pennsylvania, 1990.
The International Turquoise Annuals, vol. I and II, 1975 and 1976 (only two published) Impart Pub, Reno, NV. Note in vol. I the article on pages 31–55 by D. Allen Penick, “Turquoise, the Mineral that’s an Accident.”
Carl Rosnek and Joseph Stacy, Skystone and Silver, Prentice Hall, Englewood Cliffs, New Jersey, 1976.
Joseph E. Poque, Ph.D, The Turquoise, A report to the National Academy of Science, vol. XII, Second and Third Memoir, 1915. Reprinted in 1974 by Rio Grande Press, Inc., Glorieta, NM. (This reprint includes a foreword and details on Southwestern turquoise mines by Rex Arrowsmith and an excellent reference list. )
Stuart A. Northrop, Turquoise and Spanish Mines in New Mexico, University of New Mexico, Press, 1975.
Stuart A. Northrop, David L. Newman, David H. Snow, Turquoise, reprinted by General Printing and Paper Co., Topeka, KS. A reprint from El Palacio, vol. 79, No. 1, 1973, Museum of New Mexico.