New Mexico Mineral Symposium — Abstracts
50 Shades of Blue - Arizona Style
In 1880, Robert Ridgway was appointed the first full-time curator of birds at the Smithsonian. In addition to his significant contributions to ornithology, he also developed a systematic color nomenclature for naturalists. In 1912 he published Color Standards and Color Nomenclature, which continues to be used by ornithologists throughout the world. In an effort to determine just how many shades of blue there actually are, this book was used as a reference. It is not just about calling something reddish-blue or navy blue, but to provide consistency to the various shades of blue. As a result, one could spend a lot of time just discussing color nomenclature and never get to the confusion caused by paint manufacturers who feel the need to change their color names on a periodic basis. Starting with black and white, then red, then green or yellow and then green and yellow, blue does not show up in a language until there are at least seven colors named. Fairly low status for such a beautiful and otherwise important color.
Man’s fascination with Arizona’s blue minerals dates back millenia. Although azurite and lapis figure prominently in European and Middle Eastern histories and art, for Arizona the interest was mainly in one blue mineral, turquoise. As far back as 700CE, ornamental objects of turquoise have been discovered in archeological excavations. Turquoise was considered magical by the native populations in Arizona and New Mexico and used in commerce as far away as the Aztecs in central and southern Mexico. Turquoise Mountain, north of Kingman, was the site of extensive prehistoric mining. In 1898 Blake described benches and terraces that were evidence of significant efforts to extract turquoise from the quartz veins. This was tedious work requiring the building of fires against the rock faces and then quenching the fires with water to crack the rock.
Fast forwarding all the way to the 1870s interest by the newest inhabitants of the arid southwest in the blue stained outcrops were exploring for gold, silver and ultimately copper. The blue minerals of note, besides turquoise, were chrysocolla and azurite, which indicated the tops of what would become the great copper mines of Bisbee, Clifton-Morenci, Ajo, Globe-Miami, Ray, Mineral Park, and Bagdad.
The range of blues exhibited by Arizona’s minerals do not quite cover 50 shades, as it turns out. Most of the minerals are inherently blue but a few are stained by other elements to produce their vivid blue colors. They range from rather common species to the very rare, from micro- size crystals to ones large enough to excite every collector.
The show theme for the 2016 Tucson Show is “Shades of Blue Minerals of the World.” It seems appropriate to acknowledge and highlight some of the possible specimens Arizona may be able to contribute to the displays in support of this theme. While this examination could have been done on a locality by locality basis, it seemed to make more sense to proceed with an alphabetical examination and using a backward order Z to A, and saving azurite for last.
The first mineral is turquoise. It was found in the oxidized zones of most of Arizona’s open-pit copper mines. It has been commercially extracted from the Pinto Valley and Copper Cities (Sleeping Beauty) Mines both during active mining and for years following the cessation of copper production in the Globe-Miami district. In the Morenci Mine, a contractor mined turquoise there for decades. In the 1960s the rules were such that if a PD employee bent over to tie a shoelace in the wrong area, he could have been subject to discharge. Bisbee Blue® was the name Warren Matthews gave to the turquoise from Bisbee’s Lavendar Pit. He not only mined the material in the pit and the large waste dump but he sold it at his store overlooking the pit.
Mineral Park was also the location of commercial and midnight mining of turquoise. After a night of collecting turquoise from one of the dumps the collectors found themselves surrounded by Mohave County sheriff deputies. It seems there had been a bank robbery and when their vehicle had been spotted, the collectors were carrying out their turquoise in bags that appeared similar to money bags and the general appearance of the collectors was similar to the bank robbers’ description. Ultimately, their innocence was proven when the bags were emptied to reveal turquoise, not $5, $10 and $20 bills. The deputies went on their chase of the bank robbers and did not have time to arrest the turquoise diggers for obviously trespassing.
One of Arizona’s rarest blue minerals and one of its most famous species is spangolite from Bisbee. While the type specimen is labeled from Tombstone, and almost anything is possible, it is most likely from Bisbee. The world’s finest specimens came from Bisbee and the best specimen is probably the one in MIM.
The type locality for shattuckite, a copper silicate, is the Shattuck mine in Bisbee. However the best crystallized material came from the New Cornelia Mine in Ajo. Masses weighing in the pounds were recovered and the material was thick and hard enough to be cut and polished.
Scheelite is included in the list, not because of its orange color in daylight or under artificial light but because of its strong blue-white fluorescence. The Rogers/Cohen mine in the Dos Cabezas Mountains of southeastern Arizona produced some of the best scheelites in the U.S.
Rosasite is one of the copper carbonates found in fine specimens in several of Arizona’s mines, most notably the Silver Hill Mine north of Tucson, the Silver Bill Mine at Gleeson and Bisbee.
Several of Arizona’s mines have produced post-mining sulfate minerals, starting with the United Verde Extension Mine in Jerome and these resulted from the mine fire. In the past 40 years, Dick Graeme and his sons Douglas and Richard have documented and collected a number of these sulfate minerals in the underground mines of Bisbee. They include ransomite and boothite, along with the much more common chalcanthite.
The next two blue minerals were first discovered at the New Cornelia mine in the late 1950s. Papagoite and Ajoite are also copper silicates and provide two very different shades of blue from Arizona.
The two representatives for “L” are linarite and leadhillite. Some of the world’s best linarites have been collected at the Mammoth-St. Anthony Mine at Tiger and at the Grand Reef Mine at Klondyke. In the case of linarite its color is blue. Blue leadhillite occurs as the finest specimens in the U.S. at Tiger, but in this case the blue is due to copper impurities because pure leadhillite is colorless.
The type locality for Kinoite is a drill hole in the Helvetia area of Arizona. The collector’s specimens were discovered at the Christmas mine where crystals are rare but rock covered with thin layers of kinoite have been produced both during mine production and as the result of collectors working the dumps and pit benches.
Hemimorphite from the 79 mine has been produced for decades. Hemimorphite is white or colorless in its purest forms but fortunately, there are enough impurities to give the best of this mine’s specimens several attractive shades of blue.
Diaboleite is another rare lead copper species from the Mammoth-St. Anthony Mine, where world-class specimens were recovered. Crystals over an inch long and associated with leadhillite and caledonite were found during the last period of mining in the 1940s.
The “Cs” are probably the best represented letter starting with Cyanotrichite from the Maid-of-Sunshine Mine at Courtland and the Grandview Mine in the Grand Canyon. Connelite from Bisbee is a deep blue mineral, most commonly massively crystallized in chunks of cuprite and rarely as free-standing crystals. Chalcoalumite is a robin’s egg blue botryoidal mineral for which Bisbee is the type locality. It is found by itself and as coatings on botryoidal azurite. Caledonite is another rare lead copper species from the Mammoth-St. Anthony Mine, where world-class specimens were recovered. Finally, chrysocolla is found in a number of Arizona’s copper deposits including Ajo, Bagdad, the Live Oak Mine in Miami, the Old Dominion in Globe, Ray and uncommonly in Bisbee and Morenci. The chryscolla is associated with drusy quartz crystals and chalcedony style quartz which makes for very attractive specimens. In addition, when the chrysocolla is the coloring agent in chalcedony, gem silica can result, producing some beautiful blue gemstones.
Beryl actually does occur in Arizona and even has produced a few okay specimens. The Sierrita Mountains south of Tucson have a number of small pegmatites that have produced beryl crystals up to over ten inches long. Cores of some of the crystals were truly aquamarine and 1 and 2 carat stones were cut. Recently the miarolitic cavities in the Santa Teresa Mountains have yielded a few notable aquamarine crystals and clusters.
And we finally get to the “A” minerals. Starting with aurichalcite, the best specimens are from Bisbee and the 79 mine. If you have or have seen blu calcite from Bisbee, it is actually aragonite. In a conversation with Dick Graeme about these blue specimens, only the aragonite crystal structure can contain the copper salts which give these mineral its vibrant blue coloring.
The king of Arizona’s blue minerals is azurite. Fine specimens have been recovered from Bisbee, Ajo, Morenci, Old Dominion and the Carlota Mine near Miami. Specimen production from Bisbee, Morenci and the Old Dominion date from as early as the 1880s and 1890s. The best azurites from Ajo were recovered between 1958 and 1962. The Carlota Mine has produced its lustrous azurite crystals as recently as the last four years.
Robert Ridgway, Azurite, turquoise, chrysocolla, copper, Sleeping Beauty, Morenci Mine, Pinto valley, Shattuck mine, linarite, leadhillite
36th Annual New Mexico Mineral Symposium
November 13-15, 2015, Socorro, NM