NOTE ON THE DEFINITION OF BORODAYEVITE [AG-5(FE,PB)BI-7](13)(SB,BI)(2)S-17

The original definition of borodayevite as the P-12 member of the pavo nite homologous series (NENASHEVA et al. 1992) is discussed. Re-examin ation of published chemical data on borodayevite reveals that the mine ral can be assigned both to the P-11 member in the pavonite homologous series and to the L-6 (or L-4,L-8) member in the lillianite homologou s series. The theoretical crystal structures of P-11 and L-4,L-8 homol ogues were constructed in order to compare the derived cell-parameters and the theoretical powder patterns with the published data. No fit w as found between the X-ray data of borodayevite and of the theoretical P-11 homologue. A closer fit exists in this respect between borodayev ite and the theoretical L-4,L-8 homologue suggesting that the new mine ral might belong to the lillianite homologous series. Comparisons betw een borodayevite and treasurite Ag7Pb6Bi15S32 - the only L-4,L-8 homol ogue known as far - show major chemical differences, making unlikely t he existence of a solid solution between the two minerals. Therefore, borodayevite may still be considered a distinct mineral.