43 
native, variously mineralized with sulphur, in simple and 
double combinations with other metals, especially with iron, 
antimony, arsenic, and lead; also oxidized, and in many 
compounds with acids, especially with carbonic, phosphoric, 
and arsenic acids, sometimes in great abundance. These 
ores frequently exhibit very fine shades of red, blue, and 
green, and are thus the ornaments of mineral collections. 
All copper ores by themselves colour the flame of the blovr- 
pipe green, and if they are first moistened with hydro¬ 
chloric acid, a dark blue ; and by this test the faintest traces 
of copper may be recognised. All of them, when heated 
with borax, give a bluish-green pearl, which, in the inner 
flame, or on the addition of a grain of tin, takes on a red 
colour of separated oxide or of metallic copper. Most of 
them, on being properly heated with soda, yield a grain of 
copper on the charcoal, which may be distinguished by its 
ductility and red colour. All the compounds are poisonous ; 
the solutions in acids are green or blue, and are precipitated 
by smooth iron or zinc plates. 
Fig. 6—8.—Native Copper. 
Crystallises in the various forms of the regular system, 
cubes, octahedrons, dodecahedrons, etc. The crystals are, 
however, for the most part distorted, so that prismatic and 
wedge-shaped forms of all kinds arise, as seen in the spe¬ 
cimen, Fig. 7, from Katherinenburg; sometimes icosa¬ 
hedrons are found in combination with the cube, as Fig. 
6, which is from Lake Superior in the United States, 
where crystals of an inch in size frequently occur. Arbo¬ 
rescent and shrub-like forms, like Fig. 8, which is from 
Cornwall; dense, irregular masses, of from one to two 
tons, have been found at the Urals, in New Caledonia, at 
Lake Superior, and more lately in Van Diemen’s Land. 
It is often perfectly smooth, as if polished; in other cases, 
tarnished brown-red, as in Fig. 8. The streak is copper 
red, highly lustrous; the fracture hackly, the hardness 
2*5—3-0, and the specific gravity 8‘4—8’9. The compo¬ 
sition is generally pure copper (Cu), often with traces of 
silver, gold, andiron. That from Lake Superior is fre¬ 
quently mingled with native silver, and is found in a ser¬ 
pentine amygdaloid. It occurs in many of the mines of 
Cornwall and Devon, in the trap-rocks near Stirling, the 
new red sandstone near the railway tunnel at Mauchlirie in 
Ayrshire, etc. The largest blocks are found in this country 
in the serpentine near the Lizard, where they have been 
found of half a ton weight. Most of the copper of com¬ 
merce is obtained, however, from the different copper ores, 
especially from copper pyrites, cuprite, azurite, and mala¬ 
chite, and a good deal also from the cupriferous slate, as, 
for example, in the Mannsfeld. 
Copper was, under the name of Cyprian ore, used by 
the ancients, partly by itself, and partly in combination 
with tin in a bronze-like alloy, for weapons and household 
vessels of different kinds, and is yet widely applied to the 
manufacture of kettles and distilling apparatus, to the 
covering of roofs, sheathing of vessels, to plates and cylinders 
for smoothing clothes, paper, etc., electrotyping and different 
works in the arts, as wore for telegraphs, musical instru¬ 
ments, etc.—all purposes for which its tenacity, elasticity, 
and durability in the atmosphere and under water render 
it peculiarly suitable. Yellow metallic mixtures of great 
variety are produced by alloying it with tin and zinc, and 
are known as bronze,, gun and bell metal , pinchbeck, Dutch 
gold , brass , etc. With nickel and zinc it forms white 
alloys, which are known as German silver , tutenague, etc. 
and, to a certain extent, take the place of silver. With 
arsenic it forms the alloy known on the Continent as 
white copper . From the waste of copper different colouring 
stuffs, used in chemical preparations, are made, such as 
verdigris, Scheele’s green, blue vitriol, etc. Many prepa¬ 
rations of copper are also used in medicine, in painting, 
and in printing; in chemistry, as re-agents, etc. 
SULPHURETS AND SULPHATES OF COPPER. 
The copper ores containing sulphur are very frequent, 
and often contain, in addition to the sulphuret of copper, 
sulphurets of iron, antimony, arsenic, and lead, sometimes 
also silver and gold, in which case they are principally 
applied to the production of the noble metals. The sepa¬ 
ration of copper from the common metals above mentioned 
is effected by various, often very complicated processes, 
especially by repeated heating, concentration, and the use 
of black oxide of copper, which is obtained either by cu- 
pellation or the amalgamation process; sometimes also in 
the moist way. 
Figs. 9 and 10.— Copper-glance, Yitreous Copper, 
Chalcosine. 
Crystallises in right rhombic prisms, sometimes with 
truncation of the acute lateral edges, as Fig. 10, a small 
group from Cornwall; dense masses, of a leaden to a steel- 
grey colour, are more frequent, sometimes exhibiting an 
indigo-blue tarnish, and more or less metallic lustre. The 
streak is bluish or blackish-grey, tolerably friable, of even 
fracture, 2 -5 —3'0 hardness, and 5'5 —5*8 specific gravity, 
opaque. It is a sub-sulphuret of copper, Cu 2 S, composed 
of 20’27 parts of sulphur and 79 - 73of copper. Before the 
blow-pipe it fuses, the sulphur is consumed, and a grain of 
copper is left on the charcoal. It is one of the most valuable 
copper ores, which occurs especially in Cornwall, the Ban- 
nat, in Connecticut, in small quantities also at Rudelstadt 
in Silesia, and as the petrifying medium of small pieces of 
the fruit of a cypress (Cupressites Ullmanni), under the 
name of Frankenberg corn-ears, in Hessia, also at Nassau 
and the Erzgebirge. 
The Copper-indigo or Covelline is an indigo-blue, 
almost triturable, simple sulphuret of copper; dull, opaque, 
of 1'5—2-0 hardness, which principally occurs with copper 
pyrites at the Schwarzwald, also in Salzburg and Thu¬ 
ringia. Fig. 11 represents such a piece from Herrensegen 
in the Schapbachthal, where the indigo-copper partially 
covers the copper pyrites. In Salzburg it is said to have 
been found in hexagonal prisms. 
Figs. 12 and 13.— Erubescite, Variegated Copper Ore. 
Crystallises in regular octahedrons, which are fre¬ 
quently irregularly aggregated on one another, as in Fig. 
13, a specimen from Cornwall. More frequently it has been 
o 
