202 THE MINERALS OF NEW SOUTH WALES. 



two miles from the head of the Hunter River. Dr. Thomson 

 determined its composition, hardness, and specific gravity to be as 

 follows : — 



Analysis. 





Alumina 



97-90 



Iron sesquinoxide 



1-39 



Magnesia 



•63 



Lime 



•52 



10044 



H. = 9. Sp.gr. = 3-59. 



BarMyite. — This name has been given in Victoria to the opaque 

 magnesia-coloured variety. 



Adamantine Spar. 



Found at Two-mile Flat, Uralla, Bingara, Inverell. When cut 

 and polished en cabochon this forms a very handsome ring stone. 



Emerald. — Beryl. 



Chem. comp. : Silica, aluminium and glucinium. Hexagonal 

 system. 



The name emerald is usually reserved for the deep green 

 coloured stones fit for jewellery, while the less beautiful and pale 

 varieties are termed beryls. 



The emerald is said to occur mixed with granite detritus in 

 Paradise Creek, and near Dundee. Also in gneissiform dykes on 

 the summit of Mount Tennant, and at Lanyon to the west of that 

 mountain ; in the granite at Cooma, and in Mann's River with 

 other gems. In some cases the beryl is probably meant. 



The beryl is much more common, it is found at Elsmore 

 associated with quartz and crystals of tinstone. The beryl crystals, 

 which are often very thin and fragile, are seen interlaced with and 

 seated upon tin crystals. 



At Ophir the beryl occurs in white felspar with quartz and 

 white mica ; one crystal is -§ in. through, of a pale transparent 

 yellow green colour and vitreous lustre. Sp. gr. = 2*708. 



A greenish coloured opaque beryl in small hexagonal prisms has 

 been found in the Shoalhaven River east of Bungonia; the crystals 

 are associated with mispickle, and in some cases they penetrate it. 



Chrysoberyl. — Cymophane. 



Chem. comp. : Glucinum aluminate. Rhombic system. 

 The late Mr. Stutchbury mentions that he found a fragment of 

 this gem in the Macquarie River. 



