200 THE MINERALS OF NEW SOUTH WALES. 



Well-formed short columnar crystals of augite are not un- 

 common. They are abundant at Newstead, Cameron's, and Middle 

 Creeks ; near Guntawang ; Pretty's Plains, near Molong ; and near 

 to the Pigeon House. At Bruno waterfall, Callallia Creek, with 

 mesotype and arragoiiite in a vesicular and amygdaloidal basalt, 

 which rest upon columnar basalt. 



Smaragdite containing native copper, occurs in a hard elvan 

 porphyry at Molong Creek, and near to Dowagarang (the Old 

 Man Canobolas). 



DlALLAGE. 



Chem. comp. : Calcium and magnesium silicate. Occurs in small 

 bronze-green coloured crystals in the serpentine of Bingera, Wari- 

 alda, and Kelly's Creek, Gwydir Biver, with chrome iron. The 

 crystals are thin, and more or less brittle ; translucent. 



Hypersthene. 



Chem. comp. : Calcium, magnesium, and iron silicate. Found 

 near the Lagoons, west of Gulgong. 



Chrysolite Peridot. — Olivine. 



Chem. comp. : Magnesium silicate. Bhombic system. Transpa- 

 rent bright green coloured specimens of chrysolite are common in 

 most of the gold drifts. Found in the Shoalhaven and Hunter 

 Bivers. Old Trigomon. Associated with the various gems in Gt. 

 Mullen Creek, which falls into the Cudgegong ; also at Two-mile 

 Flat, Bingera, and other places. The exterior often has a white 

 opaque enamel-like crust. 



Gem Stones- 

 Corundum. 



There are several forms of this substance — alumina. The blue 

 is known as the sapphire, the green as the oriental emerald, the 

 red as the ruby, the hair-brown as adamantine spar, the magenta- 

 coloured as barklyite, and the common dark-coloured ones as 

 corundum and emery. 



Sapphire. 



Chem. comp. : Alumina or aluminum sesquioxide. Hexagonal 

 system. The usual forms met with in New South Wales are 

 double-sized pyramids, sometimes combined with the basal pninacoid 

 or other pyramids ; the prism is less common. Perfect crystals 

 are, however, rare, the majority of the specimens being either 

 fractured or waterworn. There appears to be no record of their 

 having been found in situ. In certain cases it would appear from 

 their sharp and unworn edge that they had not travelled very far. 

 H. = 9. Sp. gr. = 349 to3-59. 



