Paek. — On Occurrence of Bare Minerals in N.Z. 367 



about a mile south of Tapu. The vein was very irregular, 

 and less than ^in. in thickness. The matrix was rusty- 

 coloured quartz. The strike of the vein was N.N.E. to 

 S.S.W., and it was contained in highly-decomposed brown- 

 coloured tuffs, which are probably of pyroclastic origin, judg- 

 ing from the occurrence in them of a thin seam of cotily shale 

 a few chains distant from this point. 



Melanteeite (Ferrous Sulphate). 



This mineral results from the alteration of iron-pyrites. 

 It is found in large quantities in many of the old workings in 

 the Kurunui Hill and Old Caledonia Mine, where it occurs in 

 thick layers incrusting the floors and sides of the drives, and 

 as stalactitic masses which frequently reach to the floor, and 

 thus block up the passages. The exposed surfaces are always 

 invested with a layer of greyish- white ferrous sulphate, which 

 occurs in the form of fine acicular filaments possessing a beau- 

 tiful silky lustre. The solid mineral possesses a bluish-green 

 colour and a coarsely crystalline structure. 



This mineral is found in metal mines in all parts of the 

 world, but its vast development at the Thames is of an excep- 

 tional character. 



ViviANiTE (Hydrated Phosphate of Iron). 



Early in 1892 Mr. James Macky, jun., manager of the 

 Norfolk Battery, presented the School of Mines with a large 

 specimen of this mineral from what was described as an ex- 

 tensive deposit which had been discovered during the opera- 

 tion of sinking a well on the property of Mr. Matthew Hunter, 

 situated near Mercer Railway-station. This vivianite occurs 

 in the earthy form. It is soft and friable, and possesses a 

 deep-blue colour. It is a very pure variety, and contains 

 about 26 per cent, of phosphoric acid. I have not been able 

 to visit, and personally examine, this deposit, but, judging from 

 the details supplied by Mr. Macky, it would appear to be by 

 far the largest known in New Zealand. 



