Investigations by small-angle X-ray scattering of nanoparticles in the irizing labrador and features of mineral powders at the nanoscale

Abstract

The small-angle X-ray scattering method was used to study samples of iridescent and noniridescent labradorites, albite and quartz. An X-ray unit fitted with a U-shaped Kratky collimator was used in the research at the wavelength of 1,51 Å. 0,1-0,2 mm thick labradorite plates and powdered minerals were used as the samples; the plates were cut across the crystallographic axis. Anisotropic scattering has been found in the plates of iridescent labradorite for the first time in the history. This scattering is probably connected with structural defects in iridescent crystals, whose typical dimensions are 50-150 nm. The curves of small-angle X-ray scattering obtained for iridescent labradorite and albite in the «scattering intensity» – «inverse space vector module» coordinates show expressed rectilinear dependence on the log-log scale. The fractal parameter D of these curves equals 2. This proves that the investigated plagioclase powder particles are characterized with flat surface within a wide range of dimensions from 10 to 150 nm. Similar scattering characteristic were received when investigating the quartz powder. It may be preliminary hypothesized that these features of X-ray scattering do not depend on cleavage characteristics.