There are many works devoted to the internal structure of pyrite, mainly related to the deposits. This article is devoted to the structure of pyrite, formed by metasomatic way in magnetite ores and skarns of Sarbaisky contact-metasomatic iron deposit. The internal structure of pyrite was studied by means of electrolytic etching using 10-20% NH40H solution as an electrolyte. The allotriomorphic and hypidiomorphic grain structure of aggregates and the shape of individual grains were revealed. Outside the ore deposit, the cube shape dominates, whereas the ores are most characterized by pentagondodecahedrons and octahedrons often in combination with the cube. Therefore, the shape of pentagonal and hexagonal, various trapezoids, less often squares, is quite characteristic for random slices of pyrite ...

The method of indentation has been known for a long time. For the first time it was proposed in 1906 by V. Bauman and E. Gein for the determination of sulfides. Hein for determination of iron and manganese sulfides in various grades of steel, and later - by R. O. Zhirkovsky and a number of Swiss researchers for diagnosis of opaque minerals in polished slides. In the Soviet Union, further development and improvement of the method was carried out by S. A. Yushko and I. A. Yushko and I. S. Volynsky, and recently - V. I. Tikhomirov ...

The article presents new data on intrusive rocks of the Sarbaiskoye deposit, obtained as a result of the works of the geological party of the Leningrad Mining Institute.Sarbaiskoye magnetite ore deposit is one of the largest among the deposits of the Kustanai iron ore province. I. A. Kochergin and G. A. Sokolov consider this deposit to be a contact-metasomatic deposit, confined to the contact of a multiphase intrusion of diorite-porphyrites with volcanogenic-sedimentary rocks of the Lower Carboniferous. Among the intrusive rocks I. A. Kochergin distinguishes: 1) pre-metallic: [a) diorite-porphyrites of the main intrusion; b) vein diorite-porphyrites; c) metadiorite-porphyrites]; 2) post-ore: [a) vein quartz diorite-porphyrites; b) syenite-porphyrites: [according to G. A. Sokolov, microgranite porphyries].

Sarbaiskoye deposit of magnetite ores in the Kustanay region lies among dislocated and metamorphosed Paleozoic rocks of monoclinal bedding, falling to the west at an angle of 45-50° and overlain by horizontally bedded Meso-Cenozoic sediments with a thickness of 70-130 m. E. A. Mazina attributes the ore-bearing volcanogenic-sedimentary strata to the Lower Carboniferous (middle-upper Vise-Namur).