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BESIDES BLUE MINERALS ARIZONA HAS SOME FANTASTIC
SUNSETS SUCH AS THIS PHOTO NEAR CAVE CREEK.
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I have noted before in these postings (especially
see August 21, 2012) about my first trip, in 1967, to Salt Lake City, Utah, so
that I could attend graduate school. I
was just a small town Kansas kid and came from a high school of 48 students
(that is total for all four grades)! If I
misbehaved in school it was likely that my father knew about it before I
reached home after the end of classes.
Word seemed to travel rapidly in a small town. The great “things” about
this childhood included participating in a variety of sports, getting a pretty
fair education (four years of math, science, and English) and being able to
spend any free time tromping around the countryside collecting rocks, fishing, camping,
and hunting for a mythical cave (see posting July 23, 13).
I attended the University of South Dakota and
completed a MS degree and now was heading west (with a spouse of 5 days) to
experience life as a frontiersman (or so I dreamed) and get another degree. But, upon popping over the Wasatch Mountains
and seeing Salt Lake City I was flat-out scared. Wow, this was a big city (~250 ka) and the
University was probably really large (everything is relative to the
times). We had little money but found a
small apartment where the rent was $35 every two weeks, and we were off.
At that time the University of Utah followed an “old
school” model with three different and separate
departments: Geology, Geophysics, and
Mineralogy; each area had a chair and faculty. All departments had good faculty members;
however, I became quite fond of two in geology—Armand Eardley, a well-respected
structural geologist and stratigrapher Lee Stokes (my major adviser).
The Utah Geological Survey was intimately associated
with the departments and their Associate Director was an economic geologist by
the name of Eugene Callaghan. In 1968
the three departments consolidated into the Department of Geology and Geophysics
and Callaghan became the Chair. In
retrospect, I suppose securing an external chair was an appropriate political
move that would not “favor” a single department. At any rate, I was spellbound when listening
to Callaghan talk about his past careers and travel spanning most of the world’s
continents, especially his stint as chief geologist for Cyprus Mines Corporation,
and his field work in 1930’s Nevada. They were fascinating stories.
Over the years since leaving Utah in 1970, I had not
really thought much about Dr. Callaghan except when I read an article detailing
some of the interesting geology of Cyprus.
Not being a mineralogist, I often had difficulty understanding the
complex ore mineralization present on that island!
This winter, while rummaging through some mineral
specimens at a small venue at the Tucson shows, I came across a thumbnail
specimen with a smear or two of blue color.
Now, I am a sucker for blue minerals so shelled out a couple of dollars and
tucked it away. Imagine my surprise when
I returned home and checked out the “blue specimen” labeled Callaghanite from
Nye, County Nevada, and found that the mineral was named after the former
department chair at the University of Utah--one of those serendipitous moments.
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PHOTOMICROGRAPH OF A CALLAGHANITE VEINLET WITH TINY
NODULES OF WHITE DYPINGSITE [Mg5(CO3)4(OH)2-5H2O]
or HYDROMAGNESITE [Mg5(CO3)4(OH)2-5H2O. THE NODULES ARE LESS THAN 1 MM IN WIDTH.
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| INCRUSTATION OF BRIGHT BLUE CALLAGHANITE. WIDTH OF "BLUE" SECTION ~1.1 CM. |
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MAGNESITE OR HYDROMAGNESITE (MATRIX) WITH A BLUE INCRUSTATION OF CALLAGHANITE. WIDTH OF SPECIMEN ~2.7 CM.
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Callaghanite was named by Beck and Burns (1954) and
was described as “…small, azure-blue crystals from the working pits of the
Gabbs Refractories Inc. Gabbs, Nevada [Nye County] and is…a hydrated basic
copper, magnesium, calcium carbonate, Cu4Mg4Ca(OH)14(CO3)2-2H2O
[now
noted as Cu2Mg2(CO3(OH)6-2H2O]…The
mineral occurs near peridotite dikes intrusive into magnesite and dolomite…part
of the Luning formation of Upper Triassic age...At the contact between magnesite
and diorite, magnesite has been changed to brucite and diorite has become more basic
by assimilation of magnesia. Apophyses of diorite within brucite may be changed
completely to serpentine. A thin band of forsterite often marks the boundary between
the serpentine and brucite…[Callaghanite] generally is found within this serpentine-forsterite-brucite
zone where it occurs as tiny disseminated crystals, as encrustations, and as veinlets.
The field relationship of the mineral suggests that it is hydrothermal in origin.” Beck and Burns also suggested that the hydrothermal solutions
normally would have precipitated azurite but because of the magnesium and
calcium in the surrounding rocks, Callaghanite was formed.
Callaghanite is usually reported as being “very rare”
and for decades was only known from the type locality. Beginning in 1988 reports begin to trickle in
about rare occurrences in Austria, Germany, Italy, and Oklahoma, USA. See Mindat.org for references.
The Deseret News of Salt Lake City, reporting on the
death of Dr. Callaghan, reported: his distinguished professional career spanned
62 years and seven continents. He received his B.A. and M.A. in geology from
the University of Oregon and a Ph.D. in geology from Columbia University in 1931.
From 1928-46, he conducted research and geologic mapping in Utah, Nevada,
Massachusetts, Puerto Rico, and South America for the United States Geological
Survey. In 1946, he was appointed professor of economic geology at Indiana
University. During 1949-57, Dr.
Callaghan directed the New Mexico Bureau of Mines and Mineral Resources,
Socorro, New Mexico. After 1957, he served as international consultant to Haile
Mines Corp., DeLiew, Cather & Co., and other firms for which he conducted
surveys in Cuba, Mexico, Canada, Turkey, Iran and other countries. From
1958-60, he was chief geologist for Cyprus Mines Corp., conducting studies in
Cyprus, Greece, Israel, Arabia, Spain, Portugal and Morocco. During his retirement (post 1972), Dr.
Callaghan continued geologic consulting and attending professional conferences
in Ireland, Scotland, Kenya, People's Republic of China, Australia, and Antarctica,
among others.
As a summary note, Callaghanite actually was named
for Dr. Callaghan’s time as Director of the New Mexico Geological Survey and
his work with magnesite.
REFERENCES
CITED
Beck, C.W. and J.H. Burns, 1954, Callaghanite, a New
Mineral: American Mineralogist, v. 39.