Scientific publications

The results of the study of the structural parameters of several morphological varieties of Palаeоproterozoic (2,1–1,9 Ga) shungite rock quartz from the Maksovo deposit of Zazhoginsky field (the Onega structure, Karelian craton), compared with standard quartz samples of chemically precipitated, hydrothermal and pegmatite genesis, are reported.

The parameter values of the crystalline lattice, the coherent scatter region and the crystallinity index and the degree of perfection of crystalline structure were estimated for all quartz varieties by X-ray structural analysis. The structural parameter values obtained were compared to divide all the morphologically different quartz samples analyzed into two groups. The structural parameters of shungite rock quartz of group I were found to be similar to those of chemically precipitated quartz, while those of group II to hydrothermal and pegmatite quartz. All of the shungite rock quartz samples analyzed are represented by well-crystallized nanosized α-quartz.

Shungite carbon was revealed in all quartz samples by thermal analysis and combined scattering spectroscopy methods. Differences in the burning-out temperature of the carbon, which is part of various quartz samples, have led us to conclude that carbon with a certain secondary structure and degree of activity is characteristic of each morphological quartz variety.

The effect of carbon concentration in the samples on the spectral properties of quartz, reflected in combined scattering spectra, is shown. The similar crystalline structure values of quartz from various shungite rock types could be due to the effect of nanostructured shungite carbon on the growth of quartz crystals. Our study has shown that quartz, like carbon, is an important constituent of shungite rocks responsible for the basic physicо-chemical and technological properties of Maksovo rocks, and could be regarded as an untraditional type of mineral product.