CARBONADO FROM THE LENKOISH REGION, BAHIA STATE (BRAZIL) - MINERAL INCLUSIONS, PHYSICAL-PROPERTIES, GEOCHEMICAL FEATURES, AND FORMATION CONDITIONS

A series of mineralogical and geochemical data suggest kimberlite gene sis of a black porous carbonado sample from Brazil. The mineral inclus ions in it are mainly rare earth alumophosphate (goyazite) and titaniu m oxides (anatase, brookite, and rutile). Rutile is syngenetic to diam ond, and the other minerals are epigenetic. Carbonade is characterized by a significant content of rare earth elements. Their main concentra tor is goyazite, which was probably formed as a result of a substituti on of primary minerals (apatite,perovskite) with a high content of the se elements. The uniformity of the relative distribution of lanthanide s in investigated carbonade, black zonal diamond, and various kimberli tes indicates their generic relationship.