Formation & Sources of Turquoise


Turquoise is a secondary mineral. It is deposited in veins and as nodule (rounded masses) near the surface by circulating ground waters carrying copper, aluminum and phosphorus leached from earlier
rocks. The tabular deposits are seldom sufficiently wide to produce thick stones. The fissures are often so narrow and irregular that the mineral recovered can be used only as turquoise matrix. It is found occasionally in alluvial deposits as nodules, but it weathers fairly rapidly when exposed at the surface.

 Sources and recovery methods

(Note : The numbers in parentheses in this portion of the text refer to approximate locations of sources on the accompanying maps.)

The ancient mines near Nishapur, in the northeastern corner of Iran (Persia), about fifteen miles west of the town of Meshed, are usually considered to be the source of the finest turquoise. Before World War I, turquoise mining was a leading industry in Persia, providing the government with a substantial annual revenue, but production today is at a virtual stand-still. For hundreds of years nearly western Asia came from this famous source, and for many decades it supplied the American trade as well. The entire deposit lies on the southern slope of Ali-Mirsai, one of the peaks of the mountain range in the region. The turquoise occurs both in veins in an altered trachyte (pronounced TRACK-ite), which is an extrusive igneous rock, and in alluvial deposits. The finest stones are found in the alluvial source, where they occur as pebbles weathered to a chalky-white material on the outside but containing cores of fine quality turquoise. Other Persian deposits are situated near Kerman and Yezd these, however, have never been important producers.

The oldest turquoise mines in the world are situated on the Sinai Peninsula, on the north side of a valley called Maghara Wadi. Here the gem is disseminated in thin seams through a red iron bearing sandstone, as well as in a porphyritic igneous rock. As early as 5500 B.C. (before the first dynasty), the Egyptians used turquoise for personal adornment, as proved by beads found in prehistoric graves antedating the dynasty period. By the time of the first dynasty, about 3200 B.C.), the kings of Egypt were sending expeditions of miners to Sinai. These royal mining expeditions were highly organized, often comprising two thousand or three thousand laborers with a military escort. The long journeys were a usually begun in November and concluded in May, before the summer heat became excessive. In at least one instance, however, three years elapsed before the adventurers returned home. The mines were worked in this manner over a period of approximately two thousand years, until late in the twentieth dynasty (about 1100 B.C). The quantity of turquoise obtained was never very great, although historical records show that about 882 pounds were produced in one year. Malachite was a by product, and the miners usually brought back manganese and copper ores for use chiefly in glazes and enamels.

In the nineteenth century, about 1845, the old mines at Wadi Maghara were discovered by an Englishman and worked on an extensive scale from about 1854 to 1866, when operations were discontinued. Some what later a Frenchman worked the mines {or a short period, and in 1903 English promoters obtained a concession. This last attempt, however, was a complete failure, and work was abandoned after a year or two. Even now, occasional stones are picked up in this region by the Bedouins, who barter them in exchange for articles they need; but all known deposits on the Sinai Peninsula are completely exhausted, and there is little reason to believe that further discoveries will be made that will lead to a revival of systematic mining.

Other foreign sources of little or no importance are Tibet, China, Australia (Queensland, Victoria and New South Wales), Mexico (Sonora and Zacatecas), Peru, Chile, Turkestan and Afghanistan.

Today, the United States is the world leader in the production of turquoise, most of which comes from the southwestern states. Occurrences in Arizona are near Tombstone, India.

There are reports of Turquoise from Tibet and Andhra Pradesh in Mining is usually a very simple process that requires little subsurface shaft sinking and tunneling, for turquoise is never found in quantity at depths exceeding one hundred feet. Usually, it is exposed on the surface, and good material is often at a depth of but a few feet. An open cut trench or shallow pit suffices for working the shallower deposits, but for extensive operations at slightly greater depths a shaft is usually sunk and tunnels extended horizontally there from at intervals along the vein. Most turquoise deposits are found in arid reigns, where drainage is no problem. This, plus the limited extent of most deposits and their shallow depth, usually warrants little in the way of expensive or elaborate equipment. Thus, most turquoise mining is rather primitive. After the rock has been loosened, it is broken by hammers and raised to the surface in buckets hoisted by rope and windlass. Additional crushing is then done, after which it is hand picked for rejection of unsuitable material.


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