Lee and Be Moraes — Ferrazite. 353 



Aet. XXIII. — On Ferrazite? A new associate of the 

 Diamond; by T. H. Lee and Luiz Flokes de Moraes. 



Among the voluminous researches of the late Eugen 

 Hussak some of the most interesting are his patient 

 investigations of the dense minerals found in diamond- 

 washing, which extended over a number of years. 



Apart from the great number of minerals studied and 

 determined by him and made known to the scientific 

 world by the publication of his posthumous work "Os 

 satellites do Diamante/' edited by our colleague Dr. 

 Jorge Belmiro de Araujo Ferraz, considerable and valu- 

 able material exists in the Hussak mineral collection, 

 acquired and conserved by the Brazilian Geological Ser- 

 vice, in which our colleague encountered and handed to 

 us for analysis a number of "favas" 1 with Hussak's own 

 label < < Pb-Al hydrophost. D.-3.095.Neu ! " < 



From the results of a preliminary analysis it appeared 

 that, in addition to lead, barium was also present, which 

 led us to carry out a complete analysis, leading to the fol- 

 lowing results : — 



Combined water 14-20 



Lead oxide 45-63 



Barium oxide 8-87 



Lime traces 



Alumina 3-48 



Phosphoric anhydride 26-24 



Silica 2-44 



100-86 



Considering the silica to be present as kaolinite, and 

 the excess of alumina over and above that required 

 by the silica to be present as wavellite, the composition of 

 the ' ' f avas ' ' should be represented as follows : — 



New Mineral Kaolinite Wavellite 



Combined water 12-48 0-71 101 



Lead oxide 45-63 — — 



Barium oxide 8-87 — — 



Alumina 205 1-43 



Phosphoric anhydride . . . 24-92 — 1-32 



Silica — 2-44 — 



1 Favas: English equivalent "Beans." This name is applied to certain 

 dense rounded nattish pebbles found with the dense residues from gravel 

 in the diamond-washers bateas. 



