PAPER ON " CHILLAGOE GARNET ROCK." 



By FRANK E. CONNAH. 



Read before the Royal Society of Queensland, November 2^th, 



1908. 



Introductory. — In all reports dealing with the geology 

 of the Chillagoe District mention is made of the close 

 association in the ore deposits of garnet rock with the 

 copper minerals ; in fact, Mr. Alexander Stewart, in his 

 report for th3 Chillagoe Proprietary Company, in 1898, 

 referred to it as being " one of the features of the field " 



Occurrence. — Garnet rock occurs not only in the lime- 

 stone country at Chillagoe itself, but also in other parts 

 of the district, notably at Mount Garnet, where no lim)- 

 stone is found in the immediate vicinity. Instances have 

 come under my notice of garnet rock being found in the 

 outcrop of lodes which showed no signs of copper or other 

 valuable metal, but very seldom is copper absent. 



Garnet Mineral. — Garnet being a mineral of variable 

 type, it is a matter of some interest to fix the type of the 

 mineral of this district. So far as I am aware, the only 

 analysis which has been published is one which was included, 

 as being of interest, in the report of Mi*. Stewart referred 

 to. As I know that this analysis was made in a bush 

 laboratory, under extremely adverse conditions, I have 

 obtained a sample of the mineral from, the same locality, 

 and have submitted it to a careful analysis, the result of 

 which 1 now lay before you. 



Garnet Rock. — Before going further, I would remind 

 you of the difference between garnet mineral and garnet 

 rock, the latter term being applied to rock of which garnet 

 mineral is a chief constituent. 



Analysis of Garnet Mineral. — The analysis presented 

 here is of the garnet mineral. The sample was obtain ad 



