54 THE MINEKA.LS OF TASMANIA. 



in a vein of garnet at^ the Hampshire ; with 

 barite at the Wilmot River ; as a flaky coating 

 on limonite at Nolan's Creek, near the Pieman ; 

 in chlorite, with blende and galena, at Laurel Creek, which 

 is a tributary of the Blyth River. At the Dunyan Range, 

 near Circular Head, small quantities have been obtained. 

 At the Rio Tinto Mine, Savage River, it occurs with mag- 

 netite and actinolite, much of the metal at this locality 

 being in the form of felted masses that are composed of 

 capillary filaments. At the Argent River, near the Reni- 

 son Bell Tin Mine, native copper occurs cementing together 

 granular quartz and other rock fragments, the patches of 

 rock being at times almost encased with the metal. It 

 also occurs at numerous other localities in small quantity, 

 but not, so far as known, of any special importance. 



91. Corundum (Oxide of Aluminiuyn ) . 



A well-known mineral occurring in many varied colours, 

 several of which have received well-known appellations, 

 such as ruby, sapphire, corundum, and emery. It answers 

 to the formula Al^ Og, and crystallises in the rhombo- 

 hedral system. Its common mode of occurrence as crystals 

 is in six-sided prisms, which very rarely exhibit any 

 tendency to flat triedral terminations. It is more com- 

 monly granular or in the amorphous condition, or again as 

 small rolled fragments. It may be opaque to translucent, 

 and is sometimes almost colourless; but it usually shows 

 some tint of grey, brown, or greenish, with an occasional 

 chatoyant lustre. The term corundum is by common use 

 confined to the dull-coloured opaque variety, and emery to 

 the granular dark-coloured form that is usually intermixed 

 with magnetite. The ordinary dull-brown coloured form 

 of this mineral is often met with in the stanniferous drifts 

 of the north-east mining district. It gradually merges in 

 tint and translucency to the clear blue sapphire, although 

 clear gemstones of the highly valuable Oriental standard 

 are of exceptional occurrence. Nevertheless fine coloured 

 stones have been and are still found, that are almost, if 

 not quite, equal to the average from the East. The colour 

 of the gem as occurring in this island varies through all 

 shades of blue, green, and purple, and they are not rarely 

 parti-coloured — at times showing tints of blue and yellow 

 in the same stone. The valued asteriated variety is not 

 uncommon. A somewhat fine example of the parti-coloured 

 sapphire was obtained in the Weld River, weighing 264 



