Morenci TurquoiseMorenci Turquoise; Arizona Mine, Morenci, Clifton - Morenci District, Shannon Moutnains, Greenlee County, Arizona, USA. An open pit copper mine located in the NΩ Section 16, T4S, R29E (Clifton 15 minute topographic map), owned by Phelps Dodge Corp. Map Reference: 33∞5; 26"N, 109∞21' 58"W.
Morenci turquoise was mined in southeastern Arizona until approximately 1990. It is located very near the New Mexico border, and ranges in color from classic high electric blue to light azure. Prehistoric Indians who valued the stone for its deep blue color were the first to discover the deposit. These people adorned themselves with rough hewn beads and carved talisman made from the mineral.
Morenci is often associated with an unusual black matrix of irregular iron pyrite, which looks metallic when polished. Although they are rare, stones with unusual birds-eye patterns, red matrix and an occasional layer of silver have also been found. The Morenci name is derived from the large open pit copper mine owned and operated by the Phelps Dodge Corporation. Early examples of this striking turquoise were of the "lunch box" variety, meaning they were carried out of the mine by workers and miners.
Morenci is well known; it was one of the first types of American turquoise to find its way to the market and is always difficult to obtain because the mine was depleted so long ago. It is believed that the best Morenci ever produced was discovered in the late 1960's to early 70's. During this time period, the mine produced a high, electric blue variety with iron pyrite inclusions. Since Morenci is no longer being mined, and because of its striking color and unusual matrix combinations, high grade natural Morenci is a valuable, highly collectible mineral.
USGS; Arizona.--In Arizona turquoise ranks first in terms of value of production and is also the best known of its gem materials. Nearly all important deposits of turquoise are located near copper occurrences or in copper deposits in arid desert regions of the world. Thus, the world famous turquoise deposits associated with certain of the large Arizona copper deposits are to be expected.
Turquoise is, or has been, mined from a number of these copper mines as a byproduct, usually by outside contractors. The financial and operating terms of the collecting contracts vary from mine to mine. Some of the operations are little more than the efforts of individual commercial collectors; some are essentially full-scale mining operations that are simultaneous with, but separate from, the regular mining operations; and still others operate on an on-call basis as turquoise is uncovered by the regular copper mining operation. Regardless of the size or sophistication of the initial mining or recovery operation, the actual turquoise is recovered by careful extraction using hand methods.
