Kyanite is one of the three Al2SiO5 polymorphs, the other two being andalusite and sillimanite. The three aluminum silicate polymorphs (kyanite, sillimanite, and andalusite) are of major importance in metamorphic and experimental petrology because of their abundance in metamorphosed lutitic rocks and relatively simple chemistry.
The crystal structure of kyanite sampled from crystalline schists of Sebeş-Lotru Series (Negovanu, Cibin Mountains, Romania) from Getic nappe of Southern Carpathians has been refined using X-Ray powder diffraction data and the Rietveld method. The Rietveld refinements were carried out using the computer program Diffracplus TOPAS 4.1 (Bruker AXS GmbH). Pseudo-Voigt (pV) profile function was used for the fit of the peaks. Rietveld refinement using X-Ray powder diffraction data of kyanite sample in space group P-1 (No. 2), a=7.1491Å, b=7.8792Å, c=5.5912Å, α=89.75º, β=101.16º, γ=105.92º, Z=4, confirm the basic kyanite structure.