Every year, the scope of application of X-rays to solve both theoretical and practical problems is expanding more and more. One of these problems is the use of X-rays for the purpose of identifying crystalline substances. The indispensability of the X-ray method of v-research has a particularly strong effect in geological and mineralogical in practice for a number of minerals of great industrial importance, such as iron, nickel, manganese, copper ores, clay and cement minerals, small fractions of rocks, ocher Mo-, Sb-, As-, W-minerals, etc. , due to the powderiness of the objects, all existing research methods (chemical, optical, mechanical and others) either cannot give positive results at all, or are used with great difficulty. In these cases, the only effective method is the X-ray method. Also, the only applicable X-ray method is when establishing. certain features or changes in the crystal structure of the substances being studied. When studying isomorphic groups of minerals, this method provides indispensable services in elucidating the characteristic features of isomorphic substitution and associated changes in the crystal structure. When studying a crystalline substance, the X-ray method should be used along with all existing research methods, because it makes it possible to establish perhaps the most important of all constants of a crystalline substance - the dimensions of the unit cell, and the arrangement of atoms or ions in the structure. The X-ray method of research is gaining increasing “authority” among chemists, mineralogists and mine workers. However, the widespread use of this method for identification circuits of crystalline substances is still greatly hampered by the lack of a more or less complete X-ray reference manual adapted for diagnostic purposes. The scattered works in the literature on individual minerals or groups of minerals, in which X-ray data were presented, did little to eliminate this shortcoming since, firstly, they were not adapted for identification purposes and, secondly, they affected a relatively small range of minerals. In later works of 1935-1936. some authors try to adapt x-ray data for identification purposes. However, in these works, the problem of creating an X-ray detector is solved only in a particular form - for certain groups of minerals studied by the authors.
This work - a direct continuation of the work of V. I. Mikheev - is the implementation of part of a large and urgent task of compiling an X-ray detector, conceived by Prof. A. K. Boldyrev. It consists of two parts. The purpose of the first part is to replenish the number of reference powdergrams (debyeograms), the second is to determine the mineralogical composition of two stone casting products (obtained from an experimental stone foundry installation at the Research Institute of the Leningrad Mining Institute) by comparison with the data of the reference powdergrams.
This work is one of the links in the chain to create an X-ray detector for minerals. The principles of constructing an X-ray detector, as well as the advantages of the X-ray method of powder in the diagnosis of minerals and in relation to deciphering the mineralogical composition of mixtures, are given in exhaustive detail by Prof. A.K. Boldyrev, V.I. Mikheev, G.A. Kovalev and V.N. Dubinina in the work “X-ray determinant of minerals” part I, so we will not touch on these issues here. We only note that at present the problem of creating an X-ray detector is so urgent that in a number of X-ray laboratories (Leningrad Mining Institute, Central Scientific Research Geological Prospecting Institute in Leningrad and the Institute of Applied Mineralogy in Moscow) the corresponding topic was put forward and work began directly on preparing material for the X-ray detector.
At the beginning of this century, E. S. Fedorov created a method for determining a substance by the shape of its crystals, which he called “Crystal-chemical analysis” (29). This method, based on measuring the angles between the outer faces of crystals, was an important fundamental and practical achievement of crystallography. Over the next few years, this method, which in its essence is best called goniometric diagnosis, was significantly simplified by Fedorov’s school. Currently, the Fedorov Institute and the Central Geological Prospecting Institute (TsNIGRI) are compiling a “Crystal Determinant” (2), which will enable goniometric diagnosis in its new version to enter, along with optical diagnosis, into the daily practice of a crystallographer, chemist, and mineralogist. The main advantages of goniometric diagnosis are the complete absence of substance consumption, comparative speed of determination and the same degree of simplicity of diagnosis both in the case of simple and in the case of extremely complex substances. The main disadvantages of the goniometric method are the need to have the substance in the form of crystals and the variability of the external shape of crystals of the same substance. The second drawback may in some cases make it impossible to determine the substance by goniometric method. This drawback is especially noticeable in Barker’s version (16) of the goniometric diagnosis (20, 328, 329), to a somewhat lesser extent in Fedorov’s “Crystallographic Analysis” and to an even lesser extent in the version embodied in the “Identifier of Crystals” mentioned higher.
