45 
Malachite. —Green carbonate of copper. It occurs as incrustations, botryoidal 
or stalactites, with a fibrous structure, also earthy. In colour it is green, and 
generally opaque, but sometimes translucent. Its hardness is from 3 to 5*4, and 
specific gravity about 4. It is composed of carbonic acid, 19*9; copper oxide, 71*9; 
and water, 8“2, and will dissolve with effervescence in acid. 
Azurite.- Blue carbonate of copper. Pound sometimes crystalline, but generally 
massive and earthy. It is of a deep blue colour, and varies in hardness from 3*4 to 
4*5, whilst its specific gravity is about 3'6. It is composed of carbonic acid 25*6, 
copper oxide 69*2, water 5*2. 
The most common ore of copper met with at the surface is a mixture of iron 
and copper oxide and copper carbonate, resulting from the decomposition of the 
copper pyrites. The mass is of a liver colour stained with green in patches. 
The presence of copper in an acid solution can always be determined by the 
addition of ammonia until solution is alkaline, when it will be a bright blue 
colour. The green colour it imparts to the flame is also a reliable test. 
Copper ores are found over a large portion of this Colony, but have only been 
worked in the Northampton and Roebourue districts. Very little is being done at 
present, owing to the low price of copper, although the ores here are of a very high 
percentage; the lodes are large, and in neither place is there any great distance to 
cart. 
Copper is used in coinage, alloyed with tin, to form a bronze. It is also 
alloyed with zinc, when it is called brass; but the most extensive use to which it is 
at present put is in the manufacture of copper wire, which is largely used for 
electrical purposes. 
The great falling off in the demand for copper is due to iron being used to 
replace it m ship building, whilst the great fall in price is also due to the discovery 
of the large lodes in Spain, where labour is so cheap. 
Lead. 
Symbol, Pb. ( Plumbum ) ; atomic weight , 207; specific gravity, IP35. 
Lead has been known and worked from very early times. It is a soft metal 
of a bluish grey colour, when freshly cut, with a strong metallic lustre, which 
tarnishes rapidly on exposure to the air, the surface being coated by a layer of 
carbonate of lead. 
It is so soft that it will leave a mark on paper, its hardness being 1*5. 
Lead is very malleable and ductile, but its tenacity is far inferior to all the 
other ductile metals. 
It melts at a temperature of about 617° F., and begins to volatilise at a red 
heat. 
It is very easily distinguished from all the other white metals by the fact 
that it marks paper and is very malleable. 
Lead occurs in nature mostly as sulphides and carbonates, but it is also found 
in combination with several other elements. 
Galena. —Lead sulphide. — This mineral occurs either crystalline or massive; 
its colour and streak are silvery, with a metallic lustre. Its hardness is 2’5, and 
specific gravity 7*5, being composed of sulphur 13*4, lead 80‘6. It generally 
contains some silver, and often gold, without which precious metals it hardly pays 
to work at the present time. It is distinguished from silver by its cubical cleavage. 
Gemsite — White Lead Ore ; Lead Carbonate.—This is found crystalline, 
fibrous, and massive, of a white or greyish colour and brilliant lustre. It, is very 
brittle, its hardness being 3*5, and specific gravity 6*46, being composed of 
carbonic acid, lfi*5: lead oxide, 83*5, and is reduced with ease to a globule of lead 
on charcoal. 
