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Morenci Turquoise; Arizona Mine, Morenci, Clifton-Morenci
District, Shannon Mountains, Greenlee County, Arizona, USA. An
open pit copper mine located in the N1⁄2 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.
