Specific physical and chemical properties of anthracites may be explained by the differences in chemical structure of basic structural units (BSUs) and in various spatial arrangements of BSUs, that is, the texture. The structure and the texture of anthracites correspond with their optical properties. Thermal treatment causes the changes in the structure of BSUs and rearrangement of the texture of anthracites. The character of structural and textural transformation could be determined based on the reflectance values of anthracites. Various anthracites were thermally treated to the temperature of 1800 degreesC. Maximum (R-max) and minimum (R-min) reflectance values were measured and reflectance indicatrix parameters (R-ev, R-st and R-am) were calculated for initial and heated samples, It was found that R-max, R-min, and R-ev values increase together with the temperature up to 1200-1400 degreesC. In higher temperatures, they start to decrease, while R-am parameter depending on anisotropy of the texture still increases to the final temperature of 1800 degreesC, That indicates gradual and soft transformation of the structure and the texture of anthracites LIP to the temperature 1200-1400 degreesC (arrangement of turbostratic structure) and some disturbances in textural order before the stage of graphitization. (C) 2002 Elsevier Science B.V. All rights reserved.