1942: Mineralogy

The first year of active participation of the United States in the Second World War was marked by a noticeable drop in the volume of papers published on mineralogical subjects in the United States. At the same time the inflow of mineralogical journals from other countries almost ceased, so that little can be reported concerning the contributions made by men working in other lands.

However, there are many signs that the mineralogists are more active than ever before. One evidence of this is the announcement of discoveries of sorely needed minerals. For example, during the current year announcements have been made of the finding of beryllium ore in New Mexico, and carnallite, a potash salt, in Utah. A considerable number of mineralogists have been searching for magnesium minerals, so that our rapidly growing production of magnesium metal may be increased. This search has been singularly successful.

Axis conquests during the last year have made necessary an intensified search for essential minerals in the Western Hemisphere. A little over a year ago the chromite deposits of the Philippines were being extensively surveyed; now North and South America are being searched for commercial deposits of this and other valuable metals. During 1942, bulletins were published by the United States Geological Survey on chromite deposits in Alaska, magnesium resources in the state of Washington, and quicksilver deposits in Arkansas.

Another current activity of mineralogists is in the field of synthetic gem stones. Great strides have been made in this country in the manufacture of synthetic gems since the cessation of imports from foreign countries, especially Germany. These stones are not being made for purposes of adornment, but for bearings in precision instruments. Most of the synthetic gems being manufactured at the present time in the United States are made of alumina. Natural alumina is the mineral corundum, which is better known to the public by its gem names ruby and sapphire. Synthetic emeralds (the mineral beryl) have been made for the first time in the United States during recent months.

The address of the president of the Mineralogical Society of America, given at the annual meeting in late December 1941, dealt with the development of such instruments as the polarizing microscope, the reflecting goniometer, and the X-ray, and the role played by these ingenious tools in the evolution of the science of mineralogy. The annual meeting for 1942 was cancelled.

An unusual feature of the last convention of mineralogists was a symposium on diamonds. The diamond is playing such an important role in modern industrial life that this symposium was extremely timely. The papers covered such topics as the production of diamonds throughout the world, methods of cutting, the use of diamonds in wire drawing, the drilling of diamond dies, diamond set tools, bonded diamond wheels, and criteria for the evaluation of diamonds. Immediately after war broke out in Europe diamond cutting in the United States grew from an infant industry into a large and important one.

A large and active group of mineralogists continues to be interested in meteorites. No new falls of note were recorded during the year. The internal structure of crystals as determined by X-ray photographs also attracts many research workers. An 'Introduction to X-ray Crystallography,' a textbook in this general field, was published by an American investigator during the year.

Chemical analysis of minerals is so laborious and time-consuming that mineralogists utilize other methods of analysis wherever possible. The spectrograph is being used to an increasing extent, especially to determine minor chemical constituents. Because of its relative ease in application, one investigator reporting during the year recommended spectrographic analysis as an aid in correlating igneous rocks. Another ingenious method of analysis, which avoids actual chemical assay, was described in a paper published late in the current year. The behavior of the different clay minerals while undergoing heating has been determined; therefore, a clay of unknown composition can be treated in the same manner, and the materials present determined by a study of the thermal curves obtained.

The development of these short cuts does not mean that chemical mineralogy is no longer an active field of research. Two mineralogical chemists published a paper during 1942 on the alkali metals occurring in the various minerals of the mica group. In all, forty-three different samples of micas were analyzed for the lithium, sodium, potassium, rubidium, and caesium content. Lithium was found to be present in every mica analyzed, as, of course, were sodium and potassium. Rubidium and caesium were less common. Another use of chemical mineralogy is in determining the ratio between lead, uranium, and thorium so as to determine the age of minerals. Analyses of uraninite from Spruce Pine, North Carolina, show that it is approximately 380,000,000 years old.

The study of rocks and their origins advances in widely scattered parts of the globe. A paper was published in a British journal describing a series of unusual volcanic rocks from Southwest Uganda. A German periodical contained an article on the regional petrography of rocks in the mountains of central Europe. A systematic study of the heavy minerals contained in a dike rock in Rhode Island showed that the proportion of these heavy minerals increases systematically between the top and base of the dike. Another writer described the alkaline carbonate intrusives near Bancroft, Ontario, and expressed his opinion that the presence of alkaline and carbonate minerals in these rocks can be explained best by postulating reaction between granite magma and limestone rocks. For the first time the mineralogically interesting pegmatites of the Custer Area in the southern Black Hills of South Dakota were described in considerable detail. The growing tendency on the part of the many students of granites to ascribe the origin of this rock to a recrystallization of pre-existing sedimentary rocks was countered by an American investigator who presented strong evidence that such granitization could not take place without the addition of magmatic fluid.

At least two papers appeared during the year on the application of mineralogy to problems of sedimentation. One of these involved a study of the heavy minerals in sand now being deposited on the beaches of the Texas Gulf coast. It was found that each of the principal rivers emptying into the sea off Texas carries a distinct suite of these heavy minerals; therefore, by studying the beach sands it is possible to determine the source rivers and the direction of the longshore currents distributing the sediment. The other paper counters a tendency on the part of some sedimentologists to ascribe the elongation of quartz grains in sands as due to fracture and abrasion during transport. The authors carried out a set of experiments on quartz from which it was concluded that the characteristic elongation of these grains is due to original shape rather than to subsequent transportation.

Many papers appeared during the year in the field of applied mineralogy, or economic geology. One investigator in this branch of the science studied the crystals deposited in cavities in the lead-zinc ore bodies of southeastern Kansas and northeastern Oklahoma. He determined the direction of flow of the mineralizing solutions by noting the greater growth on the 'upstream' side of the crystals.

Ten new minerals were listed in the Journal of the Mineralogical Society of America during 1942, and during the same period four previously described species were discredited. No doubt, the greatly expanded prospecting and mining activity throughout the world has resulted in the discovery of an abnormally large number of new minerals.

1941: Mineralogy

Conditions Abroad.

Research in mineralogy continued unabated in North and South America during 1941. On other continents, however, the effect of the second World War began to be felt. By the end of the year the inflow of mineralogical journals from German occupied Europe practically ceased.

On the other hand mineralogists elsewhere in Europe continued to carry on their research. The leading British journal in mineralogy continued to be issued promptly. The section devoted to annotated abstracts is slightly reduced, due no doubt to the lessened flow of publications from the continent. Late in 1940 a two-volume monograph on the minerals of the Swiss Alps was published in Switzerland. This represents a distinct contribution to the science, as the monograph covers in great detail some famous mineral deposits heretofore inadequately described. The Swedes were very active during 1941, publishing a series of papers on certain interesting mineral deposits in their country. The considerable lag in delivery of Russian publications prevents any statement as to their output, but the Russian mineralogists were still actively engaged in research in 1940.

Geological Society Semicentennial.

The present year was the semicentennial of the Geological Society of America, and this anniversary was marked by the publication of a volume on the progress made by the various geological sciences during the last half century. One chapter of the volume is devoted to Mineralogy, and another to Petrology. The author of the mineralogical chapter divides this science into its many branches, such as crystallography, optical mineralogy, chemical mineralogy, descriptive mineralogy and gem stones, tracing the development of each. He calls attention to the fact that many of the conclusions of the mineralogists of fifty years ago, based upon studies of the surfaces of crystals, but dealing with the internal structure of minerals, have been verified by recent researches conducted with the aid of X-rays. The petrology chapter, after discussing progress in petrography, a branch of petrology, and then describing the great strides made in recent years in utilizing physical chemical studies in the problem of the origin of rocks, considers the advances made in studying each of the three major rock groups, igneous, sedimentary, and metamorphic.. (See also GEOLOGY.)

Industrial Mineralogy.

Industrial mineralogy made great strides during 1941. No longer is spark plug porcelain made from the sillimanite minerals and andalusite, a process which led to an extensive search for these minerals two decades ago. Spark plugs are now made from alumina (aluminum oxide). The source mineral is bauxite, which has recently received much prominence as the sole ore of aluminum, a metal vital to the war industries. Toward the close of the year the press reported the development of a process to extract aluminum metal at a reasonable cost from clay, but this announcement has not yet been verified in the technical journals. It is a process, however, which the industrial scientists have been attempting to perfect for many years. Another recent development in the application of mineralogy to industry has been the use in abrasive wheels of diamonds, the hardest of all known substances. American-made synthetic sapphires and rubies are now being used as jewel bearings in electrical instruments. A German investigator reported in the Zentralblatt für Mineralogie early in 1941 on the hardness values of both natural minerals and synthetic minerals produced by electrochemical methods.

Scientific Investigations.

Purely scientific investigations have not been neglected. For example, mineralogists in collaboration with physicists and chemists have made extensive studies during the past year of the radioactivity of rocks, and the measurement of the age of these rocks by means of ratios obtained by chemical analyses.

Interest in meteorites continues unabated. Thirty-five papers on this fascinating subject were reviewed in a British abstract journal during the year. The presidential address of the retiring president of the Mineralogical Society of America, published early in 1941, was on the subject of problems in the study of meteorites. Fourteen essential minerals have been found in these 'celestial wanderers.' The former Keeper of Minerals in the British Museum published an account during the year of meteoric irons which have been discovered during the last century in a limited area in Great Namaqualand, Southwest Africa. About 30 of these meteorites, weighing more than 10 tons, were piled up in the Public Garden at Windhoek at the time of his visit. Many others had been removed from the country previously and sold to museums throughout the world. Furthermore, by no means all of these meteorites have been collected from the semi-arid area in which they fell. The writer of the article believes that a swarm of meteorites fell in this country in prehistoric time.

A drill hole near the center of a meteor crater in Ecton County, Texas, encountered the principal meteorite mass at a depth of 164 feet. The impact of this iron meteorite caused an outward tilting of the limestone bedrock.

Publications and Reports.

Interest continued through 1941 on the determination of internal crystal structures by means of X-rays. About 50 papers on this subject were reviewed in a British abstract journal. The same publication contained titles of 30 papers and one monograph on gems and precious stones. The monograph was 'The Story of de Beers,' a well-illustrated narrative of the discovery and mining of diamonds in South Africa. Among the papers were several on diamonds, including both the gem and industrial types, and on rubies, sapphires, emeralds, zircons, jade, opal, amethyst, agates, and turquoise. Six of these papers were concerned with North American localities. This is unusual, for our continent has relatively few precious stones.

A mineralogist and a chemist collaborated on a study of the types and causes of coloring in minerals which is a subject that has interested mineralogists ever since the beginning of the science. These investigators point out that it is possible to make a fundamental distinction between coloring due to absorption or reflection, which is dependent upon the chemical composition of the substance, and coloring which is caused by structural characteristics of the mineral.

Appearing in print in December 1940, too late for inclusion in last year's review, was an account of the discovery of natural sodium bicarbonate in large quantities at Searles Lake, Calif. A core drill exploring for marketable salts penetrated several rich beds of pure sodium bicarbonate at depths between 122 and 289 feet. An abundance of good crystals of this mineral were found in the core.

The origin of the rich nitrate deposits of Chile has long been a puzzle to the mineralogist. The most acceptable theories of the origin of these highly soluble salts have included concentration near the surface by ground waters. At the meeting of the Geological Society of America in the closing days of 1940 a geologist reported that examination of airplane photographs of this district shows that many of the deposits occur beneath surfaces which lie above the salt flats. This makes the ground water theory more difficult of application. Two other papers were presented at this meeting of special interest to mineralogists. One describes a possible new tool for the identification of polished specimens of opaque minerals under the microscope by measuring the 'reflectance,' or reflection of different wave lengths of light by means of suitable apparatus. The other paper describes the use of heavy minerals found in sedimentary rocks of the Atlantic Coastal Plain to determine the source of these sediments and thereby the geography of the past.

New Minerals.

Only 9 new minerals were listed in the American Mineralogist, the journal of the Mineralogical Society of America, during 1941. This sharp drop from the 27 listed the year before is without doubt due primarily to the absence of a number of foreign journals usually received during the year, in which many new minerals are described. Surprisingly enough the number of mineral names discredited during the year was also 9. These are minerals originally described as new, but later found by more detailed investigation to be identical with, or mere varieties of, older minerals.

Awards and Memorials.

The third Roebling medal of the Mineralogical Society of America, an outstanding award to mineralogists, was presented at the annual meeting of the Society to L. J. Spencer, retired Keeper of the Minerals at the British Museum but still an active mineralogist. Dr. Spencer has served as President of the Mineralogical Society of London, and is still editor of Mineralogical Magazine and Mineralogical Abstracts.

Several mineralogists died during 1940 and their memorials were published in 1941. Among those was W. C. Brogger, Professor Emeritus of the University of Oslo in Norway, who died at the age of 89. With his passing mineralogy lost not only its dean, but also one of its ablest investigators. The others listed were Lazard Cohn, American collector and crystallographer, Philip Krieger, economic geologist at Columbia University, and John E. Wolff, Professor Emeritus of petrography at Harvard University.

1940: Mineralogy

Mineralogists the world over continued to make important contributions to the science during 1940. To be sure, the flow of publications from abroad lessened considerably during the year, but much of this may be due to interrupted transportation services. Also, but little effect of the war can be observed in the character of the research reported upon in the scientific journals. The range of subjects of the articles published is the same as in times of peace. No doubt many mineralogists in the war-torn countries are engaged in researches which may be of benefit to the military arm, but reports of such activities are not being published at this time.

At least one book on strategic mineral supplies has appeared in the United States. This book discusses the reserves, production, consumption, uses and substitutes of such minerals as mica and the ores of manganese, nickel, chromium, tungsten, tin, aluminum, antimony, mercury, platinum, iodine, and nitrogen, materials in which the United States would be insufficiently supplied during time of war. Outstanding among deficiencies in strategic minerals in the United States is tin, for only one-tenth of one per cent of the tin consumption of this country is supplied through domestic production.

Several monographs were published during 1940 (or late in 1939) in the field of mineralogy. One such was a volume on the minerals of Peru, in which 1,617 minerals in the Natural History Museum at Lima are described and their localities listed. Of petrologic interest is a monograph on the anorthosites of the Minnesota coast of Lake Superior. These anorthosite bodies range in size from single crystals of plagioclase feldspar to masses over a quarter of a mile across.

Several new falls of meteorites were recorded during the year. Natural glass tectites, which may or may not be of meteoritic origin, continued to interest many investigators. The total number of papers on meteorites listed in a British abstract journal was 43, which is about half the number listed in each of the two preceding years. However, this does not necessarily denote lessened interest in these extra-terrestial visitors, as the receipt of foreign publications by the editors of the British journal has no doubt fallen off.

Growing interest has been observed in the last few years in the clay minerals. Through the application of X-ray techniques, the individual minerals making up a clay can be identified, and many papers during the year contained mineralogical descriptions of various clays. A surprising discovery recorded during the year was the finding of ceramic clay in Hawaii. A geologist would naturally classify an area of volcanic islands as a most unlikely place to find commercial clay, but on several of the islands in the Hawaiian group a thin layer of white, high quality clay was discovered beneath the vegetation in bog areas. A combination of poor soil drainage, high soil acidity, and reducing conditions resulting from the peculiar plant growth in such areas probably led to the development of a relatively iron-free clay from rocks originally high in iron and low in silica. These clays are of great scientific interest, but their economic value is questionable, as the thickness of the different deposits is only a few inches, and they invariably occur beneath a dense overburden of plant material and at long distances from any road.

Several reports were made on the mineralogical changes which take place during metamorphism. Contact metamorphic effects around the Katahdin granite in Maine, and at Rye Patch, Nevada, were described. A monograph on the igneous rocks and metamorphism of the Adirondack region appeared during the year.

A revival of interest in pegmatites was apparent during 1940 with the publication of at least six papers on these interesting mineral deposits in the United States alone. The localities include the beryllium-rich deposits of Mount Antero, Colorado, the lithium pegmatites of the Keystone district in South Dakota, corundum-bearing pegmatites at Glen Riddle, Pennsylvania, the tantalum-containing deposits of the Bridger Mountains, Wyoming, and still other types of pegmatites in New York and Maine.

Many papers were published during the year on X-rays and crystal structure, showing an increased interest in that branch of mineralogy. Continued investigation was also made in techniques, and an improved electromagnetic separator for mineral grains was described.

No better criterion exists of the research activity of mineralogists than the number of new mineral species discovered each year. Because of the wide geographic distribution of publication mediums, it is customary to make this count from the list published during the current year in the American Mineralogist, the journal of the Mineralogical Society of America. The actual discovery date may of course fall in an earlier year. During 1940 the number of new minerals listed in this journal was twenty-seven, which compares very favorably with the eighteen listed during 1939 and the fifteen during 1938. Likewise during the year appeared the fifteenth list of new mineral names, published by the former Keeper of minerals in the British Museum. This list covers the new names introduced during 1938, 1939, and the first half of 1940. It contains 225 names, of which 117 are recognized by the author as new minerals or as definite varieties of already existing minerals. See also CHEMISTRY; GEOLOGY.

1939: Mineralogy

The science of mineralogy continued to expand in many directions in 1939. No doubt the war will result in a curtailment of research (except in the field of war minerals) in the countries affected, but such results were not yet apparent late in 1939. During the year, contributions to science continued to appear from countries which no longer exist. For example, a comprehensive account of an unusually large group of minerals occurring in the Kladno Coal Basin of Bohemia was given in a report of the Czechoslovakian Republic.

An increasing appreciation of the value of specific gravity in determinative mineralogy led to several contributions in this field during the year. Quick and accurate specific gravity determinations are not only of value in identification of minerals, but can be used also in determining the approximate chemical composition of minerals occurring in isomorphous series. A torsion microbalance, by means of which accurate gravity determinations can be made in a very short time, was made available to mineralogical laboratories during 1939, and its operation was described in the technical literature. For the determination of the density of very minute solids, scientists in a research laboratory developed an improved technique in the use of the micropycnometer.

Centuries ago, the study of the composition of minerals led to the birth of the science of chemistry. Investigation of the chemical composition of minerals has continued through the years, and was an active field of investigation during 1939. A Japanese laboratory reported finding the rare metal beryllium in the cerium mineral allanite. Several score of papers appeared describing the formation of artificial minerals. Some of these minerals were formed accidentally during metallurgical processes, but others were made for the express purpose of determining the chemical and physical conditions necessary for their formation. The latter research furnishes valuable information as to the origin of these minerals as they occur in nature.

A specialized branch of chemical mineralogy deals with the determination of the age of rocks through chemical analyses of the radioactive minerals present in those rocks. Age determinations were made during 1939 for rocks from several places, including the Kola peninsula in Russia, northwest Canada, Connecticut, New Hampshire, Ontario, and New Mexico.

The trend of crystallography from measurements of the external forms of crystals to determinations of internal atomic structures continued to be apparent in 1939. Although much work is still done on measurement of interfacial angles of crystals, and on the determination from these data of the length and angle relationships between the crystallographic axes, a great amount of investigation was carried on in the relatively new science in which the internal structure of crystals is determined by the use of X-rays. A British abstract journal listed sixty-six papers during the year which were devoted to this phase of the science.

Some unusual discoveries of diamonds were made during 1939. A stone weighing 726.6 carats was found in a placer deposit in Minas Geraes, Brazil. It has been named the President Vargas. Of perhaps equal interest, but of opposite extreme in the dimensions of the crystals found, was the discovery and identification of over fifty exceedingly minute black diamond grains in an iron meteorite from Canyon Diablo, Arizona. Although diamonds were first discovered in meteorites in 1888, the total number of known occurrences is exceedingly small.

Mineralogists have long appreciated that the hardness of minerals varied in different crystallographic directions, and diamond cutters have known that diamonds were no exception. A report was made in 1939 bringing the variations in hardness of diamonds to the attention of mineralogists. It was found by these investigators that the diamond is hardest parallel to the octahedral faces and softest parallel to the six faces of the cube.

Appearing late in 1938, too late to be included in the report on the progress of mineralogy for that year, was a description of the mineralogy of three sulphate deposits near Calama in northern Chile. Seventy-six minerals were identified and studied. Eighteen of these, of which seven are new species, have not yet been found elsewhere. Oxidation and secondary enrichment of primary copper minerals, under the existing conditions of extreme aridity, have been mainly responsible for this remarkable suite of minerals.

Mining operations in a pegmatite in Sweden resulted in the discovery of large masses, weighing several hundred kilograms of pollucite, a caesium-containing mineral which resembles quartz in appearance. Before the discovery of the value of caesium in radio tubes pollucite was very scarce, and large specimens absolutely unknown. Active search for this mineral was started several years ago, and resulted in the discovery of large masses in pegmatites, first in Maine, and now in Sweden.

Several contributions were made in the field of sedimentary mineralogy during 1939, including the publication of a manual of sedimentary petrography. Cores of deep sea sediments were obtained, and the minerals present identified. New knowledge concerning the mode of formation of the clay minerals was obtained through synthesis of these minerals from feldspar by carbon dioxide charged water under high pressure and temperature.

Meteorites continue to excite interest. Eighty-four papers (the same number as in 1938) concerned with meteorites were listed by an abstract journal during 1939. One such paper described a witnessed fall of an australite in western Australia. Although these meteorites are abundant in Australia, this is only the second witnessed fall to be described in the literature. A meteoritic stone weighing over a ton and a half, and with a maximum dimension of 4 feet, 5 inches, was discovered in central Australia in 1937, but its description was not published until 1939. This is an exceptionally large stone.

A fair index of mineralogic research during any year is the number of new minerals which are discovered and described. During 1939 about eighteen such new occurrences were made a matter of record. These discoveries ranged in latitude from Greenland to South Africa, and every continent except Australia was represented. See also CHEMISTRY; CONSERVATION.