Pakk. — 0?i the Occurrence of Native Zinc. 385 



by the unusual weight of a soft flat-shaped stone about Gin. 

 long and 2in. wide. The stone on being broken exhibited a 

 thin slab of a dull heavy metallic substance, with an irregular 

 surface, and tapering at the edges. It was easily detached 

 from its matrix. 



This thin slab of zinc weighed about 4oz. On freshly- 

 broken surfaces it showed a brilliant metallic lustre, and a 

 white, slightly greyish, colour and streak. It was coarsely 

 crystalline in structure, with a perfect cleavage, apparently 

 parallel to the chief rhombohedron E. Chemically it seemed 

 to be pure zinc. In external appearance, but not in colour, 

 it resembles the thin flakes of native copper found in serpen- 

 tine rocks of the Dun Mountain mineral belt. Nelson. 



The formation in which the metallic zinc was found is com- 

 posed of stratified clays, sands, and gravels, intermingled ir- 

 regularly with large boulders of solid audesite and quartz. It 

 is of Pleistocene age, and extends from Waiokaraka Gully, 

 across Irishtown and Block 27, to Hape Creek. The material 

 composing it has been derived from the adjacent country, and 

 there is abundant evidence to prove that it was formed by 

 the Hape and Karaka Streams during a p)eriod immediately 

 preceding the last general upheaval of this area. 



The point where the metallic zinc was found lies in a direct 

 line with the old course of Hape Creek, which drains the 

 southern slopes of Una Hill, which is itself composed of 

 rudely-stratilied tuffs and breccias of pyroclastic origin, with 

 intercalated sheets or flows of hornblende-andesite. The gold- 

 bearng quartz veins intersecting these tuffs and breccias are 

 often highly impregnated with blende as well as pyrites and 

 antimonite. 



Metallic zinc is a substance so readily acted on by dilute 

 acids, or even acidulous waters, that it is hardly known in 

 a native state. Dana, in his " System of Mineralogy," men- 

 tions only two instances of the supposed occurrence of native 

 zinc. One is reported by Professor Ulrich, who describes the 

 zinc as having been found in a geode in basalt, near Melbourne, 

 the piece weighing 4^oz. ; the other is reported in the gold sands 

 of the Mittamitta Eiver, north of Melbourne, associated with 

 topaz, corundum, &c. 



In the present instance the zinc was found in an ancient 

 drift, and its great purity and crystalline structure strongly 

 point to its native origin. It has been deposited in the Auck- 

 land Museum. 



25 



