43 
Tlie following are the most common forms in which it occurs:— 
Argentite. —Silver Glance. — Sulphide of Silver.—This mineral occurs both 
crystalline and massive. Its lustre is metallic, colour and streak lead grey, 
hardness, 2*5; specific gravity, 7*10; composition, sulphur, 12*9 per cent., and 
silver, 87*1 per cent. It is distinguished from copper, lead, and other silver ores 
by the ease with which it can be cut by a knife, and affording a globule of silver 
when heated alone on charcoal before the blow-pipe. 
Pyragyrite. —Ruby Silver.- -Dark red silver ore.—This ore occurs both crystal¬ 
line and massive of a black to a dark red colour, with a red streak and brilliant 
lustre, its hardness, 2*5; specific gravity, 5*8; and composition, sulphur, 17*7; 
antimony, 22*5 ; silver, 59*8. It is distinguished from any other mineral, as it 
fuses easily, coating charcoal with a white deposit of antimony, and yields a 
globule of silver when fused with soda. 
Stephanite. —Brittle Silver Ore. — Black silver occurs both crystalline and mas¬ 
sive ; its streak and colour are both iron black; its hardness, 2*5; and specific 
gravity, 6*27, being composed of sulphur, 16*2; antimony, 15*3; silver, 68*5. 
Cerargrite. —Horn Silver, Silver Chloride.—This is mostly foimd as incrusta¬ 
tions, but also massive, of a grey to greenish colour and waxy appearance. It cuts 
easily with a knife, the shaving curling up before it. 
Its composition is chlorine, 24*7 ; silver, 75*3 ; and is easily reduced on char¬ 
coal. 
Up to the present no silver ores have been discovered in this Colony, and even 
the lead ores are very poor in this metal, rarely carrying more than 2ozs. to the 
ton. If silver is found it will probably be associated with copper and iron ores, 
as at Broken Hill. 
At the present time silver is very low in price, so that lodes have to be of con¬ 
siderable richness to pay to work. 
Silver is largely used in coinage, jewellery, and for plating goods to preserve 
them from oxidation; and it is also to this metal that we owe the power of 
reproducing nature by means of photography, which is due to the fact that light 
decomposes certain of its salts. 
Platinum. 
Symbol , Pt.; atomic weight , 194 4; specific gravity , 2P0. 
It was discovered in 1744 by an assayer named Woods, in Jamaica, who gave 
it its name, which means “ little silver,” from its similarity to that metal. 
It always occurs in nature in the metallic state, mostly alloyed with some of 
the rare metals, and mostly found like gold, with which it is often associated in 
the form of grains in alluvial deposits. In colour it is from pale to dark steel grey 
with a metallic lustre; it is both ductile and malleable; its hardness is 4*5, and it 
is often slightly magnetic. It is easily distinguished from other metals by its 
malleability and infusibility. 
Platinum cannot be melted by any ordinary process, but requires an oxy- 
hydrogen furnace or the voltaic arc, when it melts at a temperature of 2732° F. 
This infusibility renders it of great value in chemistry when apparatus are 
required to stand a high temperature. 
It has never yet been found in this Colony, but it may at any time, and will 
probably be associated with alluvial gold. 
The other metals which occur with it, as iridium, rhodium, palladium, and 
osmium are so rare and occur in such small quantities that they are not worth 
describing. 
