102 BUILDING STONES OF QUEENSLAND. 



A\"here the Enoggera Creek makes its wa}' betAveen Euoggera 

 Kange and Taylor Range, and are on the north side of the 

 Waterworks road across the creek. Several small quarries 

 have been worked, and in one of them a felspar-porphyrj- 

 d^^ke about nine inches A\'ide is seen passing through the 

 granite. The jointing is not at all regular and it is a matter 

 of difficulty to quarry the stone in an economical manner- 

 The stone when fresh is grey but it takes on a pinkisli tinge, 

 owing to iron staining, when the ))oulders have become 

 Aveathered. 



The granite in the hand specimen has a "' pe])per and 

 salt "" appearance and is made up of translucent ([luirtz, 

 white cloudy felspar, small flakes of biotite or black mica, 

 and in some cases hornblende and occasional crystals of 

 P3'rites. It is a fine-grained granite and this, coupled ^ith 

 the rather small amount of fine crystals of l)iotite and lioin- 

 blende, results in a lack of '" relief." The stone takes a very 

 good polish, but it does not repay in added appearance for 

 the extra cost. 



A microscopical examination of the stone shows it to 

 hax'e an average grain-size of from 1.5 — 2uiui. The fal)ric 

 is granitic, although in places it is micrographic. 



The minerals present are plagioclase, orthoclase, ([uartz, 

 biotite, hornblende, pyrites and chlorite in. decreasing order 

 of abundance (see microphotograj^h 13, plate X). The 

 felspars are rather cloudy and the l)iotite in most cases is 

 very much altered into chlorite. The ])yrites ]jresei\t in 

 the sections is in^rariably fresh. 



The occurrence of crystals of pyrites throughout the 

 rock, and of ca\ities or " \ ughs "" containing calcite, pyrites, 

 etc., is a great disad\'antage to this stone. The jnrites 

 rapidly oxidises to hydratod iron oxide which has a dirty 

 broA\'n colour aiid much depreciates the a])pearanee of the 

 stone. An examination of this stone in the l)ase of the 

 Executi\ e Building or C'entral Technical College well 

 illustrates this objection. 



A noteworthy feature of the stone is the comparative 

 iibsence of segregations and in this respect it compares very 

 favourably indeed Avith the Moruya granite of Nca^' South 

 Wales and the Harcourt granite of Victoria. Segregations 

 of either an acid or liasic nature are rare ])ut, unfortunately, 



