Rutile has been identified as syngenetic inclusion in detritic diamonds from Garças River (Mato Grosso State), and Caiapó River (Goiás State), Brazil. The inclusions, which are brown colored and prismatic in habit, have dimensions approximately 1 mm along the crystallographic c axis. The unit cell dimensions are a o = 4,59 Å and c o = 2,95 Å, measured in precession photographs. Microprobe analyses show that the rutile is almost depleted from chemical impurities; besides TiO2 whose content ranges around 99,7%, rutile contains less than 0,4% of Si, Al, Cr, Fe, Mg, Ca and Mn. Presumably, the inclusions, as well as their diamond hosts crystallized in an eclogitic environment, similar to the eclogite xenoliths found in kimberlites.
