The detailed characteristics of the feldspar from the pegmatites of the Povazsky Inovec Mts. enabled the construction of a temperature-genetic graph of the formation of pegmatites. K-feldspars are micro- to macroperthites with a wide range structural arrangement of Al-Si in the tetrahedrical position of the K-phase. The Na-phase has an exsolution, exsolution-segregation to autometasomatic character. On the basis of the content of Rb, Cs, Ba, Sr, more differentiated pegmatites can be distinguished from less differentiated. The coexistence of feldspar minerals begins at 625 °C in the feldspar-quartz-mica zone. Exsolution to 410 °C and the process of structural arrangement occur at the same time in the subsolid state. In some areas, Na autometasomatism is brought into the processes of exsolution, during which the albite zone originates in the temperature interval from 316 to 297 °C.