Cox. — On the Mineralogy of New Zealand. 



391 



is white, with glossy conchoicTal fracture like milk-opal, or with earthy 

 fracture like magnesite. At Te Tarata siliceous deposits in terraces cover 

 about three acres of land. 



Alumina. 

 Corundum, -A\. — Dr. v. Haast mentions the occurrence of the variety 

 sapphire from the western slopes of the Southern Alps (Geol. Eep., 1870- 

 71, p. 24), and in August, 1871, Captain Hutton brought another specimen 

 from Collingwood, which is now in the Colonial Museum. It is described 

 in the Seventh Museum and Laboratory Eeport, p. 18, as follows : — " A 

 rough sapphire, sent by a digger, who found it with alluvial gold at Colling- 

 wood, Nelson, is the first discovery of this precious stone in the colony. 

 The specimen, which weighs 336-9 grains, is in the form of a water-worn 

 pebble, remarkable on account of its deep blue colour on the fractured sur- 

 face, and its great weight ; but it is so traversed by fissures as to be of no 

 value as a gem. Its specific gravity is 3-869." 



Non-metallic Minerals. — Class VI. 



i Silicates of magnesia and lime, hydrous and anhydrous. 

 Silicates of alumina, hydrous and anhydrous. 

 Aluminates of magnesia and glucina. 

 Silicates of glucina, zirconia, thoria, and yttria. 

 Anhydrous Silicates of Magnesl\ and Lime. 

 Wollastonite, Ca Si. — Specimens of a massive form of wollastonite were 

 collected from the Dun Mountain by the late Mr. E. H. Davis in 1871, and 

 are now in the collection of the Colonial Museum. They have been de- 

 scribed and analyzed by Mr. Skey, who reports (Col. Mus. & Lab. Eep. vi., 

 p. 15) that the four specimens examined had the following composition : — 





l. 



2. 



3, 





4. 



Silica 



. . 48-01 



49-30 



50-62 





58-80 



Lime 



. . 46-20 



45-91 



44-88 





24-60 



Magnesia 



. . traces 



•80 



traces 





1-60 



Alumina 



. . 1-45 



1-41 



1-84 



.} 



12-20 



Iron oxide 



traces 



traces 



1-64 



Loss 



2-19 



1-19 



traces 





1-40 



Water 



.. 215 



1-39 



1-02 





1-40 



100-00 100-00 100-00 100-03 



The iron oxide in Nos. 3 and 4 is the protoxide, and No. 4 contains traces 

 of chromium. 



They are massive, confusedly crystalline, colour pure white, lustre 

 pearly inclining to vitreous on certain fractures, easily fusible to glassy 

 bead with no soda reaction. Easily decomposed by hydrochloric acid with 

 the formation of gelatinous silica ; hardness 4 to 5. No. 4 is an impure 



