BY W. F. PETTERD, C.M.Z.S. 203 



352. ZiNCiTE f Oxide of ZuicJ. 



Only known to occur as small amorphous patches on 

 siderite, quartz, and other veinstone. The colour is a 

 somewhat bright red. Heazlewood Silver-lead Mine. 



353. Zircon (Silicate of Zirconium ). 



This mineral is isomorphous with cassiterite. It forms 

 when cut and polished a beautiful gemstone, for which 

 purpose the Tasmanian specimens are peculiarly adapted 

 on account of their high lustre, in which respect they per- 

 haps excel those from all other localities, although they are 

 not, as a rule, so highly coloured as those obtained in 

 Northern New South Wales and Southern Queensland. 



As occurring here they are usually more or less trans- 

 parent. In colour they vary through many shades of 

 brown to red, and although occasionally fine clear stones 

 of good colour are obtained, they are usually much clouded 

 with darker tints. The zircon presents three distinct 

 varieties of colour, viz., the jargon, yellow-brown ; the 

 hyacinth, bright red ; and that termed zirconite, which is 

 almost opaque, and reddish-brown in colour. All three 

 are fairly abundant here. In this island it has not appar- 

 ently been obtained in situ, but doubtless originates from 

 the detritus of the granite rock. It is abundant in the 

 stanniferous drifts of the North-East Coast, where it occurs 

 with topaz, pleonaste, and quartz. Well-developed crystals 

 are of extreme rarity, as they are generally much wafer- 

 worn. The specimens from near Table Cape are, as a rule, 

 darker and brighter in colour than those occurring on the 

 tinfields ; but they are commonly more fractured, although 

 fairly good crystals are not nearly so rare. 



It has been found clear and colourless at the Blythe 

 River; in beautiful glassy and lustrous crystals, ranging 

 from one-eighth of an inch in length to extremely minute, 

 Meredith Range and North Pieman; in many colours— 

 yellow, green, and red, to colourless — Boat Harbour, near 

 Table Cape ; in many variations of colour, including bright 

 clear red. Flinders and Long Islands, Bass Strait; in large 

 numbers, often of considerable size, in drift, Moorina, Weld 

 River, Thomas' Plains, and other places on the North- 

 eastern tinfield. 



Abundant as a constituent in hornblende-gneiss, from 

 the Forth River. It occurs as grains and elongated prisms 

 which often penetrate the hornblende- 

 Respecting the zircons from Boat Harbour, Dr. Ander- 

 son writes ( " Records of the Australian Museum," Vol. VI., 



