BY W. F. PETTERD, C.M.Z.S. 17 



33. AxiNiTE (Silicate of Aluminium and Calcium with 

 Boracic Acid). 



This mineral is of some interest crystallographically as a 

 finely-developed member of the anorthic system, and 

 chemically from its complex composition, which may be 

 expressed by the equation HCag A\^ BSi^Oig where Ca 

 is partly replaced by Fe and Mn. An analysis of the Tas- 

 manian mineral from Colebrook gave the following 

 result : — 



Per cent. 



SiO^ = 45 



Fe O + Mu O = 14 



Ala O3 = 16" 



CaO = 18' 



MgO = 1 



B2O2... = 3 



Loss on ignition HjO = 



100 

 Gravity, 3-23. 



The late Professor Ulrich stated that " it is found in ill- 

 formed tabular crystals of dark-brown colour and glassy 

 lustre in the coarse-grained amphibolite of the bismuth 

 mine, Mt. Ramsay. Apparently very rare. It fuses very 

 easily before the blowpipe, and imparts to the flame the 

 characteristic yellowish-green colour of boric acid. The 

 borax bead is coloured amethystine in oxidation flame, 

 becoming yellow in the reduction flame." In all probabil- 

 ity the greatest discovery of this somewhat rare mineral 

 hitherto recorded occurred at North-East Dundas, near 

 Ringville, at the Colebrook P. A. Mine. At this locality 

 occurs a remarkable association of axinite with various 

 other minerals, which has been fully exposed by mining 

 operations with a view to utilising the copper ores con- 

 nected with the discovery. The crystals of axinite are as 

 a rule very finely developed, with the edges highly modified, 

 even much more so than the noted examples from the well- 

 known classic localities of the Dauphine, France, and from 

 Botallack, Cornwall, England. They are of a distinct and 

 peculiar violet colour, of high lustre, and at times of large 

 size. They occur intimately and irregularly associated 

 with milk-white calcite, brown augite, pale-green spicu- 

 lated actinolite, and more sparingly pale-green datolite, 

 which last is often exceedingly well crystallised. There are 

 also immense quantities of pyrrVotite, which commonly 



