46 The American Geologist. J"'-''- ^•'"-• 
HUSSAKITE, A NEW MINERAL, AND ITS RELA- 
TION TO XENOTIME 
E. H. KRAUS AND J. Rl-.ITINOER 
During the course of e:vtensive researches with the rare 
earths, which are being conducted by Prof. W. Muthmann of 
the Technical High School, JMunich, there was found to be a 
dearth of material from which the oxides of erbium and ga- 
dolinium can be obtained in larger quantities. The raw yttrium 
oxide obtainable in commerce, which- is doubtless derived from 
he most part from fergusonite proved to yield a comparatively 
low percentage of erbium. The same may be said of the pro- 
ducts obtained from sipylite, which Dr. K. Th. Postius* has 
been investigating in Prof. Muthmann's laboratory. 
Therefore, the thought suggested itself that perhaps the 
xenotime from Minas Geraes, Brazil, might lead to better re- 
sults. In 1886 Gorceixf published a paper on the xenotime 
from Dattas, near Diamantina, which he said occurred tl!ere n^ 
considerable quantities and contained a good deal of erbium, 
but no gadolinium. Through the kind assistance of Dr. E. 
Hussak of Sao Paulo, it was possible for us to obtain in a very 
short time a quantity sutilicient to conduct a thorough investi- 
gation of this interesting material. 
The material .sent by Dr. Hussak was found by a careful 
microscopical examination to be homogeneous and not in the 
least decomposed. Several crystals with well preserved faces 
were also found, so that crystallographical measurements could 
be made. These, as will be seen later, agree very closely with 
those of xenotime inasmuch as only a few analyses of xeno- 
time have been published, a chemical investigation of the clear- 
est and most transparent pieces was at once made. Tlic re- 
markable fact soon presented itself that a considerable amount 
of sulphuric acid is present in the mineral. By means of the 
soda reaction on charcoal a number of crystals were tested for 
sulphuric acid and without an exception the presence of this 
acid could be shown. This is very striking, for neither doe^ 
Gorceix mention the presence of sulphuric acid in this mineral 
•Dr. K. Th. Postius. Untersu chungcn in der yttergruppe, Inaugural Dis- 
sertation, Technical High, Munich, 1902, 1-30. 
tGorceix, Comptes rend. 1886, 102, 1024. 
