96 THE MINERALS OF TASMANIA. 



This mineral occurs massive at several of the North- 

 East Dundas mines, where it is classed under the common 

 designation of " fahl-ore," a term applied to several dis- 

 tinct minerals with the general physical characters of 

 tetrahedrite. 



153. HuASCOLiTE (S^dphide of Lead and Zinc). 



In the fine granular galena-blende ore-bodies which are 

 so characteristic of the Hercules-Read mines, a substance 

 occurs, which is apparently homogeneous, and fairly cor- 

 responds with the double sulphide huascolite. It has a 

 massive granular structure, is lead-gray in colour, with a 

 lustre rather duller than ordinary galena. It occurs 

 closely intermixed with the fine particles of galena and 

 blende, but can be separated. If the metals are chemically 

 combined, it will to a great extent account for the utter 

 impossibility of mechanically separating the lead and zinc 

 contents of these ore-bodies. A substance of similar char- 

 acter has been obtained at the Comstock Mine, Zeehan^ 

 and at the Godkin Extended, Whyte River. The mineral 

 as mined at the Hercules Mine contains approximately 35 

 per cent. Zn, 20 per cent. Pb, with a variable quantity of 

 Ag and a little Au. At the Godkin Extended Mine the 

 mineral was obtained associated with blocks of galena and 

 slugs of argentite, the whole affording high assay value 

 in silver. 



lo4. Hyalite f^^ydrated Silica). 



Occurs in cavities of a hard lode gangue in white to 

 pale-green botryoidal masses. Locality: Bell's Reward 

 Mine, Heazlewood. At the Argent Mine, Zeehan, in 

 masses of considerable beauty with opalescent reflections. 



155. Hydrocerussite (BaMv Lead Carhonafe) 



In one of the adits of the Hercules Mine, Ml. Read, a 

 white fluidal substance was observed in decomposed lode- 

 matter, which on giving up its hvgroscopic water, assumed 

 a silvery white appearance, and which under the micro- 

 scope is resolved into very minute scales, but with little or 

 no hexagonal structure. In all essential respects the sub- 

 stance agrees with this species. 



156. Hydromagnesite (Hydrocarhonate of Magnesium). 



An amorphous mineral resulting from the alteration of 

 brucite. It has not been found in a crystallised condition, 

 its usual mode of occurrence being in the form of chalk-like 

 crusts. In serpentine with brucite. Locality : Near Mt 

 Agnew. Of apparently rare occurrence, in thin incrusta- 



