X-ray structural analysis has been employed to study the effect of T on changes in the crystal structure of a natural low-albite in pegmatite from the North Baikal muscovite province. Annealing was carried out under anhydrous conditions at 1030 + or - 5oC and 1 atm (grain size 200 and 300-500 mu m, exposure 6-27 days). XRD has shown that the process of Al-Si disordering in this albite is distinguished from that in Amelia albite by the absence of intermediate structural forms. After annealing the samples for 6- 11 days, low and high albites are present. The velocity of disordering does not depend on the grain size used in the experiment. An X-ray structural study on three single-crystals of albite, annealed for 11-27 days (automatic single-crystal diffractometer; R = 0.082-0.038, allowing for thermal-vibration anisotropy) has established that low and high albites subjected to different T effects are distinguished within the corresponding series primarily by completion of the crystal structure, markedly increasing with longer annealing periods. At the same time, the anisotropy of distribution of the Na-atom electron-density increases. Moreover, it has been found that equalization in the size of the silica tetrahedra takes place under the influence of annealing in the structure of ordered albite as a result of an increase in T₁m. -D.A.B.