71 
NOTES ON STAUROLITE FROM THE MOGUMBER 
DISTRICT. 
By Edward S. Si alp son , 
D.Su., B.E., F.O.S. 
V 
( Bead November \)lh, 11)20.) 
Stanrolite, H( Fe,Mg) (Al,Fe) n Si,O l: ., is a comparatively rare 
metamorphic mineral hitherto recorded from but few localities in 
Australia. Anderson, in his Bibliography of Australian Mineralogy, 
gives no locality for it in Victoria. Northern Territory or Tasmania, 
one only in New South Wales, and two each in Queensland and 
South Australia. 
'flic existence of this mineral in a belt of country lying* some' 
where to the north-east of G ingin has been known since 1915, when 
a parcel of small (4 to 10 mm.) crystals collected from gravel in 
the valley of (Tittering Brook (Brockman River) were submitted 
to the writer for determination. The more perfect of these showed 
a combination of the faces mM 1 10)nfm' , m l b 1 (01() ) h\ There were 
imperfect indications of occasional twinning on z(232), 
Later, in 1917, a single large water-worn crystal was seen which 
was said to have come from about 13 miles N.E. of (Ungin, i.e., 
between Cullalla and Wannamal, and not far from the head of (Tit- 
tering Brook, Mog umber being about 22 miles N.N.L. ot: Gingin. 
This crystal was a combination of m 1 ( 1 10)nTiu 8 mV ('OlO)b'c 1 (001). 
it was 5 cm. in length with a maximum diameter of 4.5 cm. From 
the same locality came a boulder of rock composed ot granular 
quartz and stanrolite, the latter predominating, and occurring in 
grains of about 1 mm. diameter. 
Last year was seen for the first time the probable matrix fro n 
which these loose crystals were derived. This is a rock found be- 
tween Mogumber and Gillingarra. It is fairly uniform in texture, 
consisting of a ground mass of small scales of muscovite and grains 
of quartz, in which are embedded numerous large crystals of stauro- 
lite and hiotite. Of the two coarser constituents stanrolite is by far 
the more common, and is rather evenly distributed throughout this 
particular specimen. It is in prismatic crystals of a dark brown 
colour ranging from 1 to 5 millimetres in diameter, and 5 to 30 milli- 
metres in length. The larger sized crystals are infrequent. Twin- 
ning has been observed on z(232) but is rare. 
Quite recently a fine suite of specimens of this rock was ob- 
tained . These are of the same general type as that .just described, 
