MINERALS AND MINERAL LOCALITIES OF N. S. WALES. 39 



NOTES on some MINERALS and MINERAL LOCALITIES 

 in the NORTHERN DISTRICTS of N. S. WALES. 



By D. A. Porter, Tamworth. 



[Read before the Royal Society of N. S. Wales, June 6, 1894.'] 



Tourmaline. 

 Tourmaline occurs very abundantly at Wallangra, on the 

 Mclntyre River, some forty miles from Inverell, where veins of 

 quartz containing this mineral, are common over a large area ; it 

 exists in the greatest abundance on a ridge opposite to the Post 

 Office, and extending to the Wallangra homestead. This ridge is 

 about three-quarters of a mile in its longest extension and half a 

 mile in width, and the whole of this area is plentifully strewn 

 with broken prisms and masses of the mineral. 



The tourmaline occurs here under three different conditions : — 



1. In veins of milky quartz. 



2. In nodular segregations in the granites of the locality. 



3. In immense masses (rocks) of aggregated crystals, with 



which little, if any, quartz or other mineral is associated. 



The veins of quartz occur in great number on the ridge before 

 mentioned, and vary from a few inches, to many feet in thickness, 

 They do not appear to have any definite strike, but seem to be 

 all radiating from a very large mass or " blow " of quartz, which 

 caps the apex of the ridge. The whole of these quartz veins are 

 thickly impregnated with prismatic masses of the mineral, which 

 usually exhibit a radiated structure. The crystals of tourmaline 

 are without pyramidal terminations, or at least, none were 

 observed. Some of the quartz matrix is translucent, but most 

 of it is opaque, and varies from bluish-white to a milky-white in 

 colour. A measurement of convergence of prisms, taken from 

 part of a radiated mass, showed that some of the prisms had been 

 originally eighteen inches in length. 



