Treating of Turquoise

Editor's Note: We define treated turquoise as that which has been impregnated with dye or any foreign coloring agent, as described in Dr. Pogue's definition. In stabilized turquoise no foreign or unnatural color is added to the stone. Color occurs as a result of chemical action alone.

TREATED TURQUOISE IS OUT— STABILIZED COLOR IS IN.

From time to time turquoises that have had their color deepened or otherwise improved by artificial means come into the trade. As such stones are apt to revert to their original shade upon continued wear, those treated in this manner are not sold except in attempts to defraud.

That the turquoise may be temporarily improved in color has long been known. Muhammed Ibn Mansur in the thirteenth century mentioned that its color was strengthened by mutton fat or by smearing with butter. The Pueblo Indians of the Southwest heighten the color of their turquoises by soaking them in tallow or grease. The natives near Nishapur, Persia, often carry stones in their mouths before offering them for sale, and the dealers in Meshed are said to keep turquoise in moist earthenware pots, as by these means, also, the color of inferior specimens is temporarily improved. Doelter states that greenish turquoise becomes bluer in contact with carbon dioxide.

Off-color stones are sometimes stained with Prussian blue. Stones so treated may be detected by washing in alcohol, wiping, and soaking in ammonia, whereby the dye is dissolved; or by scraping the superficial coloration from the back of the stone with a steel blade. If the turquoise is valuable it is preferable to build a small wall of wax upon its back and partly fill the depression with ammonia, as the solvent effect can thus be noted at one point only, without harm to the specimen. By artificial light the color of stained turquoise is gray-blue and unlike pure turquoise appears cars duller instead of brighter.

One process has been patented which is stated to give a permanent coloration to turquoise. The stones are first immersed in a dilute solution of tartaric acid and copper or iron sulphate, then placed for 24 hours in a bath of alcohol to which an aniline dye, dissolved in a little water, is gradually added.

For those who wish to delve into the story of Turquoise from alpha to omega there is only one source appropriately titled “The Turquoise,” by Joseph E. Pogue, Ph.D. He is eminently qualified by his credentials as Associate Geologist, United States Geological Survey, formerly assistant curator, Division of Mineralogy and Petrology, United States National Museum, Fellow of the Geological Society of America. Dr. Pogue's great work of 162 pages represents one of the most complete treatises of any single mineral species. Originally published by the National Academy of Sciences as Volume XII, third Memoir, contents include full chapters explaining the history, mineralogy, geology, ethnology, archaeology, mythology, folklore and technology, plus almost a complete pamphlet describing the affirmative and negative aspects of treating, altering and synthesizing turquoise. This is THE BOOK, the bible of turquoise experts, and the source for all writers and collectors. This important work was out of print for many years. In 1972 The Rio Grande Press, Inc., of Glorieta, New Mexico published a reprint of the entire Pogue memoir with an introduction by Rex Arrowsmith of Santa Fe, New Mexico, a geologist, collector and trader of high standing. Sixteen new color plates were added to the twenty-three original, as was a list of turquoise mines in the United States — and other important references. The book in its attractive red, white and turquoise hard cover is available from most book dealers for fifteen dollars.

The expanding demand for Indian Jewelry has exceeded the mining industry's capacity to supply gem quality turquoise far beyond the limits of realistic credibility.

According to D. Allen Penick, recognized in the industry as one of the best qualified geologists, only three percent of the turquoise being mined can be considered of gem quality. Allowing for a reasonable margin of good to fair grade turquoise to round out the top 25 percent, the remaining 75 percent of acceptable working turquoise must come from what is known in the trade as chalk, or waste.

American turquoise production falls into two categories. In the first category the mines are worked for turquoise alone, usually by hardy individuals. The second and certainly the dominant category represents the turquoise produced as a by-product of copper mining. In Arizona turquoise is intimately associated with the copper mines who more or less regard turquoise as a nuisance. On a strict operational basis, turquoise in copper is a headache to the operators because of the high cost of labor and equipment. According to management the few millions represented in the small amounts of turquoise is not worth interrupting the normal mining operation.

There is no doubt that many of the museum pieces of turquoise originally found their way from mine to market place via the miners' “lunch bucket.” Today, copper companies forbid the individual picking up of even a fragment of copper ore by employees. Instead, commercial concessionaires enjoy privilege contracts to pick up thousands of tons of turquoise bearing copper ore for a mere one to three dollars per pound. This once worthless waste after being processed and stabilized by modern methods brings from $150 to $300 per pound.

The color illustrations on page 46 show examples of modern stabilizing from “chalk” to specimens of gem quality spider web produced by Elliott Glasser's Zone One, Post Office Box 1239, Apache Junction, Arizona 85220.

The Elliott Glasser world-wide gem and mineral enterprises include the operation of a modern turquoise stabilizing plant in Arizona using turquoise imported from all parts of the world including Australia. According to Mr. Glasser, the only mystique about the turquoise stabilizing business is the lucrative monopoly of those concessionaires who have built a multi-million dollar industry out of copper company stockholders indifference.

There is no mystique regarding the modern plastic formula based on Diallyl Phthalate and Dapon 35 available to qualified agents from any major industrial chemical company or from Elliott Glasser, who has asked us to withhold the full formula and process due to the nature of the stabilizing process which may be harmful to persons not familiar with the industrial chemicals.

The treatment of precious stones to enhance their color, or other qualities, has a long and varied history. Perhaps the earliest effort was the production of so-called black onyx from grey agate by soaking the latter first in honey and then in sulphuric acid.

Subsequent improvements permitted the dying of agate in the numerous colors familiar to commerce. Tiger eye is also altered to a variety of colors, both by acid treatment and by heating, while the procedure for turning amethyst into topaz-colored citrine quartz is also well known. Most aquamarine rough must also be heated to remove the unattractive green overtones in order to achieve the beautiful characteristic aquamarine color of commerce. And in a similar vein, tanzanite, which is usually an unpleasant muddy brown color when found in nature, is turned sapphire blue in the lapidary's oven.

How good is stabilized turquoise?

From "THE ETHICS OF TURQUOISE TREATMENT" by Dan Mayers, B.S., M.S., Geneva, Switzerland, Volume I, 1975-1976, TURQUOISE ANNUAL, Official Publication of the International Turquoise Association.

Fortunately, the lessons of science have permitted real advances in the treatment of turquoise. It is possible now to produce genuinely colour-stabilized turquoise by two separate procedures. In the first procedure, inorganic mineral salts-in particular, colloidal silica-are deposited in the pores of the stones, effectively sealing them against most attacks by moisture. Although this procedure is a substantial improvement on the highly unethical oil treatment, it still does not stabilise the stone indefinitely. However, it has the undoubted advantage that nothing unnatural is introduced into the stone, as silica is a common natural impurity in turquoise and one which greatly improves the hardness and durability of much natural turquoise, particularly that of Persia.

The most successful means of treating turquoise consists of impregnating the stone with a clear, colourless plastic which solidifies and forms a permanent and impenetrable protection of the stone's intrinsic beauty and colour. Stones properly treated in this fashion may be expected to retain their colour with the same certainty as does dyed agate, although, of course, turquoise is substantially softer than agate; and even this plastic treatment will not protect turquoise from abrasion.

When the customer buys a fine turquoise-mounted silver jewel, it should be possible for the jeweller to assure the customer that her choice will retain its sky-blue beauty years into the future as it turns into a family heirloom. This assurance cannot be given in the case of untreated turquoise. On the contrary, if the jeweller is genuinely reputable, he will feel obligated to warn his customer that, in the course of years, she may expect the stone to gradually change colour and become greenish. On the other hand, providing the jeweller has a genuine understanding of the different procedures used in treating turquoise and takes care to ensure that the stones he sells have been competently stabilized in accordance with the best scientific procedures he will be able to unhesitatingly give his client the assurance she wishes that her stone will always retain its beauty.

There is a serious question whether jewellers who make a great ethical point of selling only untreated turquoise are entitled to take quite such pride in their position when, as is ordinarily the case, they fail to warn their customers of the pitfalls surrounding the purchase of untreated turquoise jewelry.

It is in the light of the above that one must approach the subject of turquoise treatment. Basically, the ethical question involved revolves around the permanence of the treatment. If turquoise can be treated in such a manner that the colour is permanently stabilised, there can be no question as to the desirability of the process, nor as to its wholly ethical nature.

We are in no way inferring that treated and stabilized turquoise is a good buy for investment purposes, nor are we advocating the ownership or appreciation of inferior goods over the collectors' pieces shown in our "Collector Series" of 1974-75.

We happen to be closer to what is going on in the world of turquoise and are aware of the gap between the ideal and the real. The availability of gem stone quality turquoise becomes lesser as the expanding market makes more and more turquoise jewelry than ever before. Sensible buyers do not expect one thousand dollar quality for one hundred dollars. Neither does everyone buy turquoise for investment. Most people buy turquoise for its sensual appeal. They have every right to know that the turquoise which cost one hundred dollars will hold its form and color as long and perhaps longer than unstabilized turquoise.

Those who can afford the out-of-this-world prices of gem quality turquoise have something rare and precious. Meanwhile millions can afford the beauty and the ego-flattering pleasure of modern stabilized turquoise.

It's a matter of attitude, ethics and basic honesty.

We string our own liquid silver, heishi, beads and nuggets with this improved Third Hand Bead Tray. Made of light-weight plastic, the side compartment holds clips, clasps, etc. From Beads and More, 4234 Craftsman's Court, Scottsdale, Arizona 85252.