36 CATALOGUE OF MINERALS ; 
On the Charters Towers field the most auriferous mineral is 
iron pyrites, though frequently it is associated with more or less 
galena, sphalerite, and chalcopyrite ; calcite not unfrequently 
forms part of the vein stuff, and a little gypsum has been 
occasionally noticed, as in the Queen reef and North Australian. 
Pyrrhotite forms a large part of the brownstone capping of the 
reefs. Mr. R. L. Jack says that arsenic is hardly known in any 
form in the field, and that gold disseminated through the granite 
rocks themselves is occasionally evident to the naked eye. Visible 
gold in quartz is not considered a good feature by the miners on 
this field after the zone of permanent saturation is reached ; rich 
mundic containing visible gold has, however, been found in No. 1 
claim of the Old Identity reef in the neighbourhood of a fault 
which cuts the reef at the 130 ft. level between Nos. 1 and 2 
claims. In this reef barytes occurs on joints in the granite walls. 
Mr. R. L. Jack makes mention of some interesting specimens 
from the Bryan O’Lynn, Queen reef: “ One of these is part of a 
vein about one inch in width, coated on both sides with chlorite 
and coloured dark blue with minute specks of galena, and con- 
taining visible gold. Some specks of gold occur in the middle of 
a mass of crystallized zinc-blende. ‘The quartz is amorphous 
except in the middle, where both sides of a cleft are lined with 
dog-tooth crystals, the spaces between the crystals being filled up 
with gold. In another specimen the gold occurs as an isolated 
cluster of grains in a mass of milk white amorphous quartz, of a 
kind which would be apt to be regarded as ‘buck’ but for the 
visible presence of gold. A third specimen has gold in scattered 
grains among crystals of pyrites and very fine galena. A fourth 
specimen shows a mass of gold containing minute pyrites crystals 
in a matrix of white quartz.” Also in the Bryan O’Lynn a granite 
is met with, in the joints of which are scales of iron pyrites, 
assaying from 134 to 2 dwts. gold per ton ; this is worthy of notice 
as auriferous pyrites is not often associated with granite, though 
a similar occurrence has been noticed at Jimna, in the Wide 
Bay district. 
On the Black Snake gold is contained in quartz veins traversing 
granite, and containing iron and copper pyrites and sphalerite. 
On the Norton field the auriferous veinstuff is iron and 
arsenical pyrites, sphalerite, and galena, with quartz and a little 
calcite. 
At Mount Perry the chalcopyrites, which is of so extensive 
occurrence, is generally, if not always, auriferous. 
