138 



BUILDING STONES OF QUEENSLAND. 



are at Kangaroo Point, Spring Hill, near the Exhibition, 

 and at OConnelltown. 



The stone is a \ ariable one as regards colour and 

 compactness. It needs verj^ careful selection, which is 

 easily understood when one realises its mode of origin. 

 It is formed from a volcanic ash of a rhyolitic nature and has 

 been subsequently consolidated and hardened very largely 

 by the passage through it of solutions containing silica. 

 The influence of the silicification has not been equal in all 

 parts of the mass so that the stone varies a great deal in 

 the same quarry. All shades of colour from white to pink, 

 green, yellow, brown and jjurple are obtainable; these 

 colours are due to the influence of iron and manganese 

 oxides. 



The jointing is not very regular and much \'ariation 

 exists as to the size of blocks obtainable in the different 

 quarries. This stone will not stand much pressure without 

 cracking, and an investigation of an}' job on which this 

 stone has been used where it is subjected to much pressure 

 will bear this out. 



Many instances are a\ ailable where this stone has be- 

 come very much weathered and it is j^articularly prone to 



Fig. 20. St. John's Anglican Cathedral, Brisbane. 



View from East. Erected 1908-10. Main structure of Brisbane 

 tuff, external facings of Sydney sandstone. Building on right was built, 

 in part, of sandstone from Breakfast Creek quarry well over 50 j'ears ago. 



