204 



NATURE, OCCURRENCE, AND ORIGIN OF ALUNOGEN. 



Analysis of Sandstone, Two Feet in From the Cliff 



Face. 



Moisture and combined water 



Insoluble 



Alumina (AI.O5) and Iron sesquioxide (Fe 0;,) 



Sulphuric anhydride (SO,) 



100.60 100.. 54 



It will be noted that the SO 3 content percentage 

 averages 0.685, which corresponds to approximately 2 per 

 cent, of Al2(S()4^)3.18H20 in the sandstone. 



The solid incrustation was al.so analysed in duplicate 

 by Mr. Graff. His results are set out below under I. and II. 

 along with those obtained in the Agricultural Chemist's 

 Laboratory imder III, and recorded in the Queensland 

 Government Mining Journal, 1916, p. 427. 



Analysis of the Solid Incrustation. 



Mean of 



100.12 100.71 100.41 99. & 



The sample whose analysis is shown under III. waa 

 dried at lOOX'. before analysis. 



Taking the mean of I and II and assuming that the 

 insoluble material is made up of sand grains and recalcu- 

 lating to 100 per cent, we get the following results (A) which 

 can be compared with the theoretical alunogen analysis. 



100.00 100.0 



The similarity is thus seen to be very close and, although; 

 in water percentage it is lower, chemically the material 

 may be regarded as alunogen. The incrustation is soluble 

 in water and has an alum taste in accordance with the 

 properties of alunogen so that there is very little doubt 

 about the nature of the material. 



