Abstract:Refinement of the crystal structure of andalusite from metamorphic rock in Dongshan, Fujian, is shown in this paper. The structure of andalusite was de- monstrated independently by Taylor (1939),Burnham and Buerger (1961) who refined the structure to a final R value of 5.70% for 354 reflections. In this paper, the reflections (I>3δ(I))are 733 for 809, and R==0.027, which suggests that the precision of refinement is enhanced obviously. Itx the chains of alu- minium, four of the All-02 bond distances are ll.827A,two of the A11-O3 bond distances are 2 .082 A,four of the All-04 bond distances are 1.889 A;and two of the A12-O1 bond lengths are 1.839 A, two are 1.896 A; two of the A12-02 bond lengths are 1.814 A, two are 1.813A; in Si-O tetrahedroid, two of the Si-O1 bond lengths are 1.615 A,two of the Si-03,bond lengths 1 .629 A,two of the Si-04 bond lengths are 1.641A. The determine of absolute construction model of andalusite monocrystal reveals that its positive ion Al has two kinds of coordinate pattern: one is the six coordinate of distortional octahedral (All),another is five coodinate (A12). Silicon-oxide group consists of Si-O tetrahedroid linked by Al, which forms sili- cate having isolate tetrahedroid (SiO4)4-.AlO6 octahedrons joined each other take shapes of chain. The thermal parameters of atom motion of andalusite shows that the probability of island silicon-oxide group and end-group atoms rises and the factor of temperature r. e., B value, increases. No replacement phenomenon of positive ion place has been discovered in the research of several monocrystals of andalusite, which suggests that the formation environment of metamorphic belt along the Fujian coast is similar in places. The value of coordinate has no change. The metamorphic environment of low temperature-high pressure reveals that the value of coordinate is biggerr and is steady in the lattice, whereas under the condition of high temperature-low pressure the value is smaller and is in the steady state. Meanwhile,in the research. No change of bond character and constructional fragment of crystal have been found, which indicates that the andalusite belongs to the low pressure -moderate high temperature type during the progressive metamorphism. Using the ESR and electronic probe, we find a little foreignw substance -of Fe3+ in the andalusite powder, probably, the foreign substance is caused by mo- saic structure and small adherent crystal.