Amazonite-bearing pegmatites of Shartashsky granite massif form small bodies with zonal structure. The amazonite crystals occur in the central coarse-blocked part of pegmatites, in miarolas, locating in druse cavities. According to the optical absorption and X-ray luminescence spectra study, the green-blue color of potash feldspar is caused by the Pb-ions admixture in its structure. The mineralogical study of pegmatites has shown, that they have rather weak rare-metal and rare-earth specialization provided by presence of the Nb-bearing manganoilmenite, Nb-rutile, allanite, monacite, xenotime, zircon, and a loverengite-senaite series mineral. Geological relationship and chemical compositions of Shartashsky granitoids and amazonite-bearing pegmatites assumes their genetic alliance. By its geodynamic setting, the massif belong to the continental margin tonalite-granodiorite formation of the Middle Urals. The high Pb concentrations in Shartashsky granites (35-50 ppm) are triple exceeding the Pb contents in similar massifs of the region. Most probably, just this concentration provided the forming of amazonite, subsequently to the differentiation of granite magma with the higher basicity.
展开▼