Cox. — On the Mineralogy of New Zealand. 



409 



I have since examined these specimens, and find the following sections 

 of crystals, which confirm Mr. Skey's determination : — 



The hardness of the mineral is about 7, and it occurs in the more 

 quartzoze portions of a syenitic gneiss, associated with garnets, pyrrhotine 

 and chrome mica, as other accessory minerals. 



Tourmaline, n jj. Si +' II 3 Si, is mentioned by Dr. Hector in the granita 

 and gneiss of the West Coast (Jurors' Eep. N.Z. Ex., 1865, p. 266) ; by 

 Dr. v. Haast, in granite, at Mosquito Hill on the West Coast (Jurors' Eep. 

 N.Z. Ex., 1865, p. 257), and by myself in micaceous and hornblende 

 schists at Eesolution Island (Geol. Eep., 1874-76, p. 31). There are some 

 very fine specimens of schorl in chlorite schist, from Collingwood, in the 

 collection of the Colonial Museum, arranged as long, black, striated prisms 

 in broken strings which radiate from a centre ; they vary from a sixteenth 

 of an inch to a quarter of an inch in diameter. Some very beautiful little 

 acicular crystals in quartz, from Bedstead Gully, Collingwood, are also in 

 the collection ; they are of a deep black colour, and red by transmitted light. 

 A blackish green variety also occurs in the granite of Tata Island, Nelson. 



Art. XL VIII. — On a new Mineral belonging to the Serpentine Group. 

 By S. Herbert Cox, F.C.S., F.G.S., Assistant Geologist & Inspector of Mines. 

 (Read before the Wellington Philosophical Society, 21s£ October, 1882.) 

 Hectorite. — This mineral is described (Col. Mus. and Lab. Eep. xv.) as 

 an altered form of augite, but is more nearly allied to the hydrous silicate of 

 the Serpentine Group. As, however, it does not correspond in composition 

 with any described mineral, I have given it the name of Hectorite. 

 Its composition, as determined by Mr. Skey, is — 



Silica 



Ferrous oxide 

 Alumina . . 

 Ferric oxide 

 Manganese 

 Lime 



Magnesia . . 

 Water 



57-89 



18-46 



4-74 



traces 



1-99 



13-94 

 2-98 



100-00 



