Two of my favorite classes in grad school were optical mineralogy and optical petrography. As the names imply, during the first semester we used petrographic microscopes to identify minerals as seen in thin sections. I have noted previously that I was never a stellar student in undergraduate mineralogy class, mostly due to crystallography. I just had, and still do, problems with visualizing and describing, three dimensional objects. Systems, Classes, Space Groups, symmetry, etc. just fogged up my brain. I was about ready to switch to another major, which would have been my fourth, when the crystallography section ended and we moved on to the physical, and understanding, aspects of minerals. Of course, in the spring semester I hit structural geology and stereograms/stereonets and about went bananas. Who thought up these objects of torture? Why was I being punished when all I wanted to do was hunt for fossils? Somehow, I advanced in the curriculum to “fun” courses like geomorphology, sedimentary geology, and the paleo sequence.

I was sort of terrified in moving on to grad school and finding out that the optical sequence was required for graduation. Then something happened—I loved the classes, the identification of minerals in the fall and following that with petrography in the spring semester where we learned how to better understand igneous and metamorphic rocks via examinations of thin sections. My life became much better, and certainly more exciting.

At any rate, our instructor owned several professional books that were available for use and stored in the lab. For some reason one particular go-to reference stood out in my mind: Petrography of the Igneous Rocks by Albert Johannsen, a Professor at the University of Chicago. Although Johannsen was no longer living in the mid-1960s, in those days I was awed by anyone teaching at Chicago, and certainly the Field Museum paleontologists who wandered around western South Dakota. Then there was the WOW factor, a commemorative plaque on campus stating: On December 2, 1942 man achieved here the first self-sustaining chain reaction and thereby initiated the controlled release of nuclear energy. The first self-sustaining nuclear chain reactor, an “atomic pile” officially dubbed CP-1 (Chicago Pile-1), operated under the stands of the former football stadium, Stagg Field. This pile of bricks and timbers was able to control nuclear fission. And so, the race was on and never stopped.

But the most remarkable item, at least in my young mind, was that Johannsen’s tome consisted of several volumes, four or five at least. My just developing mind wondered how could one person write “so much”? As MinDat stated: “He established quantitative definitions of rock analysis and rock classifications as well as redesigning the petrographic microscope. His descriptive multi-volume Petrography of the Igneous Rocks is a classic in petrography. The scholarly opus has lasted through several editions, thousands of students, and even today can be located on web sites of used book sellers. Although numerous later authors have published multiple books on the classification and description of igneous rocks, Johannsen’s works seem to be the father that started it all. Fortunately, today’s authors have much more information supplied by modern electronic gizmos.



Johannsen’s original research appeared in over 40 scientific papers and books but his early contributions were papers dealing with improvements of the petrographic microscope, and how to identify minerals using a pet scope: Determination of Rock-Forming minerals (1908), Manual of Petrographic Methods (1918), and Essentials for the Microscopic Determination of Rock-Forming Minerals and Rocks in Thin Section (1922).



J. Swift & Son, Dick Model Petrographic Microscope, 1891.





J. Swift & Son, Dick ‘New” Model Petrographic Microscope,1910.

Johannsen, in his Manual of Petrographic Methods, described a number of different pet scopes and featured the Newer Dick Model shown above. Goren ( date unknown; see references) stated that the first scope capable of “quantitative scientific work was undoubtedly the petrographic microscope by AB Dick, whose principle he described in 1889 and which was conducted in 1891 in the catalogs of the company Swift & Son (color photo above courtesy of Dr. Yuval Goren). The “Newer Dick Model” was illustrated in the 1910 Swift catalog. I was unable to find out if Johannsen used a Dick Model scope; however, since he was an admirer of German scholarship I would bet on a Leitz!

Johannsen retired in 1937 (b. 1871) and the remaining years of his life were spent in nonscientific pursuits. Evidently, he had a interest in the nickel and dime novels of the late 19th century. Actually, it was more than just “an interest” since he wrote two volumes of the well respected The House of Beadle and Adams and Its Nickel and Dime Novels (1950). In reading this sentence I became completely confused about who/what was Beadle and Adams. OK, the following information comes from Registry.clir.org/projects/2028/.

By 1864, Beadle & Adams had sold more than five million dime novels, making them one of the most successful publishers in the country. The secret to this success was undercutting rival publishers by selling novels for a dime, which was significantly lower than the going rate of a dollar. This was achieved by using inexpensive paper, exploiting cheaper postage rates for periodicals, and reprinting previously published works. Although their popularity waned towards the end of the century, they were among the most significant and innovative publishers of their time, single-handedly responsible for popularizing the dime novel format and playing an important role in the evolution of American popular fiction. Johannsen’s novel, The House of Beadle and Adams and Its Nickel and Dime Novels (1950), was a landmark work in the study of 19th century popular literature and publishing.

While working on his book, Johannsen amassed one of the largest private collections of dime novels and story papers in the United States, that was purchased by Northern Illinois University in 1967. This collection contains 6,593 publications issued by Beadle and Adams between 1852 and 1897. Johannsen's The House of Beadle and Adams and their Nickel and Dime Novels (1950), is one of the most significant works of dime novel scholarship and bibliography of the 20th century.

In 1932 W. T. Schaller, speaking at the December meeting of the Mineralogical Society of America, described a new manganese pyroxene that he was naming johannsenite “in honor of Professor Albert Johannsen of the University of Chicago”. Because Schaller wanted to study additional specimens that were showing up from several new localities, the official publication date of the mineral name did not happen until 1938 with the publication of W.T. Schaller, Johannsenite, a new manganese pyroxene: American Mineralogist, 23 (9) 575-582. To further confuse the issue, Schaller based his description on material from Tetela de Ocampo, Puebla, Mexico, and nine plus other locales. MinDat lists two localities in Italy and Franklin, New Jersey, as the Co-Type Localities. Lauf (2010) believes the locality at Puebla, Mexico, has the strongest claim for the Type Locality. Interestingly, rockhounds collecting in the western U.S. are partial to getting specimens of johannsenite from the Iron Cap Mine in the well-known Aravaipa Mining District, Graham County, Arizona.

The Iron Cap Mine is a former surface and underground Pb-Zn-Ag-Cu-Au-Fluorspar mine where the major ores were sphalerite (zinc) and galena (lead). Mineralization is found in vein deposits hosted in the Horquilla Formation (Pennsylvanian) and the Pinkard Formation (Cretaceous). Some ore veins occur in faults between formations while others are found wholly in the limestone beds. The mine area also includes numerous intrusive veins of Cretaceous and Tertiary age cutting across Paleozoic rocks (Simons and Munson, 196).

Johannsenite is a somewhat uncommon calcium manganese silicate [CaMnSi2O6], sometimes containing iron, and is the dominant pyroxene from the Iron Cap Mine. The physical properties of johannsenite vary: color ranges from brown to black to gray to green to light blue to yellow to violet and others; it is translucent to transparent; the habit is massive to acicular needles to radiating aggregates to splintery; the luster varies from greasy to vitreous and the hardness is 6 (Mohs), although the acicular needle masses break apart easily. It usually forms in contact metamorphic zones associated with skarns. Johannsenite in my specimens is composed of massive green prismatic crystals or cleavage fragments (angles of 870 and 930 typical of pyroxenes). A second specimen of johannsenite from the Iron Cap has very dark green patches of acicular crystals.



Crystals of elongate “pyroxene-like” crystals of johannsenite. Width FOV ~ 4.5 mm.



Mass of slender, acicular crystals of johannsenite. Width FOV ~7 mm.



Johannsenite, pyroxene-like crystals with white nekoite. Width FOV ~ 5 mm.

Johannsenite is in solid solution with hedenbergite when the iron completely replaces the manganese [CaFeSi2O6] and with diopside as magnesium replaces the manganese [CaMgSi2O6]. In a process that somewhat confuses me, johannsenite alters to pink rhodonite (see Livi and Verblen, 1992, for a detailed report on this process.). The Iron Cap has produced hedenbergite associated with johannsenite but not diopside.





Clear to white to reddish brown bustamite collected from the Langban ore body, Varmland, Sweden. Width FOV both photos ~ 5 mm.

Bustamite [CaMnSi2O6] is the high temperature polymorph of johannsenite and usually forms where manganese -rich ore bodies are subjected to metamorphism/metasomatism, often in skarns. The temperature break is ~830 degrees C. Bustamite is associated with johannsenite at the Franklin Mine in New Jersey but not at the Iron Cap.



Individual crystal of manganbabingtonite from the Iron Camp Mine. Length ~2.5 mm.







Crystals of manganbabingtonite with acicular crystals of johannsenite. Collected at Iron Cap Mine. Length of left largest crystal ~3 mm.

Finally, The Iron Cap Mine is also known for: 1) the magnificent crystals of manganbabingtonite, a rare Ca-Mn-Fe silicate [Ca2Mn2+Fe3+Si5O14(OH)] that is the manganese dominant analogue of babingtonite; and 2) nekoite, a rare, white, hydrated, calcium silicate [Ca3Si6O15 · 7H2O] that was originally confused with the “zeolite look-a-like”, okenite. Nekoite is an anagram of okenite!



Botryoidal masses of white acicular nekoite crystals. Width FOV ~5 mm.




Nekoite clusters with unknown colored crystal. Width FOV ~3 mm.



RFERENCES CITED

Goren, Yuval, www.microscopehistory.com; Retrieved December 2025.

Lauf, R.J., 2009, Collectors Guide to the Pyroxene Group: Schiffer Publishing, The Limited.

Simons, F. S. and E. Munson, 1963, Johannsenite from the Aravaipa mining district, Arizona: American Mineralogist, Vol. 48, No. 9-10.

Schaller, Waldemar T. 1938, Johannsenite, a new manganese pyroxene: American Mineralogist, Vol. 23, No. 9.

OF INTEREST (taken from a Memorial written by F.F. Pettijohn). Johannsen was a Man of Letters and a Polymath.

Johannsen received a B.S. degree in architecture from the University of Illinois in 1894.

He returned to school and received a B.S. in geology from the University of Utah in 1898. He then went to the Johns Hopkins University where he received his Ph.D. in petrography in i903.

Johannsen was pre-eminent in the field of microscopical petrography. He probably was, in a sense, the greatest and last of the American school of petrographers.

He is best known for his translation of Weinschenks' "Fundamental Principles of Petrology”.

His original contributions appeared in some 40 papers in the technical journals. Chief of these is his quantitative classification of the igneous rocks.

He set a standard of excellence that puts most contemporary scholarship to shame. In a sense Johannsen's scholarship was a kind of Iiterary scholarship.

He regarded a good rock description as something of permanent value

Johannsen was a collector at heart. At the time of his retirement, he left a superb collection of nearly 5,000 rock specimens at the University of Chicago. For most of these he had thin sections.

Johannsen's collecting extended to many fields outside of geology including postage stamps, commemorative half dollars, U. S. vice presidential autographs, first editions of Charles Dickens' works including the M EMORIALS 457, famous Phiz illustrations, and dime novels

He was an accomplished artist and when a student in Utah he drew the fashion plates for the Salt Loke City Herald.

He was also skilled in oil painting. He was a photographer of merit and a Leica enthusiast long before 35 mm cameras became popular.

This cultural heritage explains to some degree Johannsen's admiration of the best in German scholarship, his own mastery of German, and his unsurpassed works in the "Handbuch" tradition.

In 1967 many Ph.D. granting institutions believed that one could not be a geology scholar without understanding and reading German. Therefore, I spent a year trying (without high success) to read German and pass the “reading test.” I passed it. Wow. Next came French, and a pass.

I and thankful to Professor Yuval Goren for allowing use of his microscope photo taken from his tome. www.microscopehistory.com This web site is an amazing and brilliant piece of work and readers should take a good look at this comprehensive history of microscopes.