432 Transactions. — Geology. 



occurs in moderate sized dark-coloured crystals, having a pyramidal (tetra- 

 hedral) form, and is associated with iron pyrites, acicular crystals of quartz, 

 Galena, and traces of copper. Its matrix is a pure amorphous quartz. 

 Specimens of blende were subsequently forwarded by the same contributor 

 from Mine Bay, Great Barrier Island. 



In the same year Mr. Davis (Geol. Eeports, 1870-71, p. 61), men- 

 tions its occurrence at the Silver Crown Claim, Thames; at page 85, Mr. 

 Skey mentions its occurrence at the Thames, and at page 149, Captain 

 Hutton also notes its presenee in the New Golden Crown Claim, in the same 

 district. He also (at page 154) mentions the occurrence of this mineral in 

 the Perseverance mine, Collingwood. 



Besides these localities Zinc Blende has since been found in the reefs at 

 Mount Arthur, whence the gold is extracted. 



All the specimens of Zinc Blende which have come under my notice are 

 of a massive character but vary somewhat in appearance. The specimens 

 from the Thames goldfield, which are well represented by those obtained 

 from the Little Agnes mine, Tararu Creek, are black resinous samples of 

 the mineral, known as " Black Jack." That from Collingwood varies from 

 Black Jack to a yellow honey-coloured Blende, containing from 59% to 

 65°/q zinc, and Captain Hutton thus describes its mode of occurrence: — "At 

 about five feet above the lode, in the felspathic slate, is a band some five or 

 six feet thick, of Zinc Blende and Galena. In the lower part of this band, 

 the Blende is bluish-black, with a metallic lustre, while towards the upper 

 part it is associated with Galena, which is sometimes crystallized, and here 

 it is of a pale yellow colour, and a resinous lustre." (Geol. Eep., 1870-71, 

 p. 150.) 



In examining this locality last year, I was led to the conclusion that at 

 one part of the mine at least this Zinc Blende and Galena formed a part of 

 the lode since it occurred associated with quartz and Mispickel, had the grey 

 felspathic slates for its hanging wall and black slates at the foot, which cor- 

 responds to the general position of the main Perseverance reef. Subse- 

 quently, however, I am informed a small shaft was sunk and the main reef 

 discovered 6 feet below this Zinc Blende and Galena vein, as described by 

 Captain Hutton, so that possibly these deposits are offshoots from the main 

 reef. The other localities where Zinc Blende has been found do not merit 

 special description, as in no other case has it been discovered in sufficient 

 quantities to prove of commercial value. 



Calamine, Zn C. — Mr. Skey (Geol. Eep. 1870-71, p. 85) describes this 

 mineral from Tararu Creek; Thames, as "lustrous transparent crystals 

 attached to Diallogite, but always external ; these are well shaped but com- 

 paratively small ; they are interspersed somewhat rarely with small rock 



