concretions, in veins or along with other copper ores- From
Cornwall, and also the Yesuvlan lavas. It is an abundant
ore in some of the copper mines of the Mississippi valley,
and yields 60 to 70 per cent, of copper. But part of what
What is the crystallization of red copper ore ? Of what does it eon-
aisr ? How doet it differ from cinnabar and red iron ore ?
Digitized by VjOOQ IC
was considered black copper in the west is an ore of cobalt.
If absolutely pure, it contains 80 per cent, of copper. It is
also found of excellent quality in large veins, in the Lake
Superior copper region.
The oxyds of copper are easily smelted by heating with
the aid of charcoal alone. They may be converted directly
into the sulphate or blue vitriol, by means of sulphuric acid,
but are more valuable for the copper they afford.
BLUB viTKioL. â€” Stdphote of Copper.
Triclinate. In oblique rhomboidal prisms. Also as an
efflorescence or incrustation.
Color deep sky-blue. Streak uncolored. Subtransparent
to translucent. Luster vitreous. Soluble, taste nauseous
and metallic. H==2 â€” ^2-5. Gr=2-2L
Composition: sulphuric acid 3 1*7, oxyd of copper, 32*1,
water 36*2. A polished plate of iron in a solution becomes
covered with copper.
Ohs. Occurs with the sulphurets of copper as a result of
their decomposition, and is often in solution in the waters
flowing from copper mines. Occurs in the Hartz, at Fahlun
in Sweden, and in many other copper regions. '
Uses. Blue vitriol is much used in dyeing operations and *
in the printing of cotton and linen ; also fi)r various other
purposes in the arts. It has been employed to prevent dry
rot, by steeping wood in its solution : and it is a powerfid
preservative of animal substances ; when imbued with it and
dried, they remain unaltered. It is afibrded by the. decom-
position of copper pyrites, in the same manner as green vit-
riol from iron pyrites, (p. 213.)
k is manufiictured for the arts from old sheathing copper,
copper turnings, and copper refinery scales. The scales are
readily dissolved in dilute sulphuric acid at the temperature
of ebullition ; the solution obtained is evaporated to the point
where crystallization will take place on cooling. Metallic
copper is exposed in hot rooms to the atmosphere after it has
been wet in weak sulphuric acid. By alternate wetting and
exposure, it is rapidly corroded, and affords a solution whic^
What is blue vitriol ? Describe it. What is said of its mode of oc-
currence 1 For what is it used ? How is it manufectured in the artsi
How is copper obtained from solutions in some mines? Describe
COPPER ORB& . , 281
Is evaporated for crystals. 400,000 lbs. is the annual con-
sumption of blue vitriol in the United States.
In Frederick county, Maryland, blue vitriol is made from
a black earth which is an impure oxyd of copper with cop-
per pyrites* The black oxyd of copper, which was fouikl
in the Lake Superior copper region, may be directly con-
verted into blue vitriol.
In some mines, the solution of sulphate of copper is so
abundant as to afford considerable copper, which is obtained
by immersing clean iron in it, and is called copper ofcemeru
taiion. At the copper springs of Wicklow, Ireland, about 500
tons of iron were laid at one time in the pits ; in about 12
months the bars were dissolved, and eveiy ton of iron yielded
a ton and a half^ and sometimes nearly two tons, of a pre-
cipitated reddish mud, each ton of which produced 16 cwtÂ«
of pure copper. The Rio Tinto Mine in Spain, is another
instance of working the sulphate in solution. These waters
yield annually 1800 cwt, of copper, and consume 2400 cwt.
Brochantite, An insoluble sulphate of copper, containing 17'5 per
cent, of sulpbudc acid. Color emerald green. In tabular rhombic crys-
tals, at Katherinenberg, in Siberia. Blackens before the blowpipe with-
out fusing. Â£ri8uvigite and Konigite are the same species.
GRBBN MALAOHiTK.â€” -6fre6Â» Corhonote of Copper.
Monoclinate. Usual in incrustations, with a smooth tube-
rose, botryoidal or stalactitic surface ; structure finely and
firmly fibrous. Also earthy.
Color light green, streak paler. Usually nearly opaque ;
crystals translucent. Luster of crystals adamantine incli-
ning to vitreous ; but fibrous incrustations silky on a cross
fracture. Eailhy varieties dull. H=3*5â€” 4. Gr==4.
Composition : carbonic acid 18, oxyd of copper 70*5, wa-
ter 11*5. Dissolves with efiervesence in nitric acid. De-
crepitates and blackens before the blowpipe, and becomes
partly a black scoria. With borax it fuses to a deep green
globule, and ultimately affords a bead of copper.
Dif, Readily distinguished by its copper-green color and
its association with copper ores. It resembles a siliceous
ore of copper, chrysocolla, a common ore in the mines of
the Mississippi valley ; but it is distinguished by its complete
^ What is the composition of green malachite 1 How is it distin-
guished ? ' '
Bolution and efl^rvescence in nitric acid The color alse
is not the bluish-green of chrysocolla.
Ohs. Green malachite usually accompanies other ores
of copper, and forms incrustations, which when thick, have
the colors banded and extremely delicate in their shades and
blending. Perfect crystals are quite rare. The mines of
Siberia, at Nischne Tagilsk, have afforded great quantities
of this ore. A mass partly disclosed, measured at top 9
feet by 18 ; and the portion uncovered contained at least
half a million pounds of pure malachite. Other noted for-
eign localities are Chessy in France, Sandlodge in Shetland,
Schwartz in the Tyrol, Cornwall, and the island of Cuba.
The copper mine of Cheshire, Conn., has afibrded hand-
some specimens ; also M organtown, and the Perkiomen Lead
Mine, Penn. ; Schuyler's mine, and the New Brunswick
copper mine, N. J. : it occurs also in Maryland, between
Newmarket and Taneytown, and in the Catoctin mountains ;
in the Blue Ridge, Penn., near Nicholson's Gap, and it is
found more or less sparingly with all kinds of copper ores.
At Mineral Point, Wisconsin, a bluish silico-carbonate
of copper occurs, which is for the most part chrysocolla, or
a mixture of this mineral with the carbonate. An analysis
of the rough ore afforded Mr. D. D. Owen, copper 35*7,^
carbonic acid lO'O, water 10*0, iron 15'7, oxygen 7,* sulphur
8, silex 13-0. Specific gravity 3*69 â€” 3-87. The vein ap-
pears also to the northwest on Blue River, and southeast on
the Peccatonica. This ore is abundant ; it has been smelted
on the spot and also exported to England.
Uses. This mineral receives a high polish and is used
for inlaid work, and also ear-rings, snuffboxes, and various
ornamental articles. It is not much prized in jewehy.
Very large masses are occasionally obtained in Russia,
which are worked into slabs for tables, mantel-pieces and
vases, which are of exquisite beauty, owing'to the delicate
shadings of the radiations and zones of color. At Versailles,
there is a room furnished with tables, vases, and other arti-
cles of this kind, and similar rooms are to be found in many
European palaces. At Nischne Tagilsk, a block of mala-
chite was obtained weighing 40 tons.
Malachite is sometimqs passed off in jewelry as turquois,
though easily distinguished by its shade of color and much
How does green malachite occur ? What are its- uses ?
COPPES OBBS. 283
inferior hardness. It is a valuable ore when abundant ; but
it is seldom smelted alone, because the metal is liable to es-
cape with the liberated volatile ingredientâ€” carbonic acid.
AZURiTE. â€” Blue Carbonate of Copper,
Monoclinate. In modified oblique rhombic prisms, the
crystals rather short and stout;
lateral cleavage perfect. Also
massive. Often earthy.
Color deep blue, azure or Ber-
lin-blue. Transparent to nearly
opaque. Streak oluish* Luster
vitreous, almost adamantine. â€”
Brittle. H=8-5 â€” 4-5. Gr=
â€¢ Composition : carbonic acid 25*5, oxyd of copper 69.1,
water 5*5. Before the blowpipe and in acids, it acts like
Obs. Azurite accompanies other ores of copper. At
Chessy, France, its crysUdlizations are very splendid. It is
found also in Siberia, in the Bannat, and near Redruth in
As incrustations and rarely as crystals, it occurs near
Singsing, N. Y. ; near New Brunswick, N. J. Also near
Nicholson's Gap, in the Blue Ridge, Penn.
Uses. When abundant it is a valuable ore of copper. It
makes a poor pigment, as it is liable to turn green.
CHHYSocoLLA. â€” SUicote of Copper,
Usually as incrustations ; botryoidal and massive Also
in thin seams and stains ; no fibrous structure apparent, nor
any appearance of crystallization.
Color bright green, bluish-green. Luster of surface ot in-
crustations smoothly shining ; also earthy. Translucent to
opaque. H=2 â€” 3. Gr=2^ â€” 2*3. Composition: â€”
Oxyd of copper
Oxyd of iron
Describe blue malaphite. How does it difier from green malachite
in composition ? What is the appearance of chrysocolla 7 its compofi-
The mineral varies much in the proportion of its constitu-
ents, as it is not ciystaliized. It blackens in the inner flame
of the blowpipe without melting. With borax it is partly
reduced. No effervescence nor complete solution in nitric
acid, cold or heated.
Dif. Distinguished from green malachite as stated under
Ohs. Accompanies other copper ores in Cornwall, Hun-
gary, the Tyroll Siberia, Thuringia, drc. In Chili it is
abimdant at the various mines. In Wisconsin and Missouri
it is so abundant as to be worked for copper. It was for-
merly taken for green malachite. It also occurs at the Som-
erville and Schuyler's mine, N. J., at Morgantown, Penn.,
and Wolcotville, Conn.
Uses. This ore in the pure state affords 30 per cent, of
copper ; but as it occurs in the rock will hardly yield one-
thiiti this amount. Still when abundant, as it appears to be
in the Mississippi valley, it is a valuable ore. It is easy of
reduction by means of limestone as a flux.
Dioptate is another silicate of copper, occarring in rhombohedral
crjrstals and hexagonal prisms. R : Rasl26^ 17. Color emerald-
green. Luster vitreous. Streak greenish. Transparent to nearly
opaque. H^S. GrsS'SS. From the Kirg^ese Steppes of Siberia.
Besides the above salts of copper, there are the follovring species,
which <are of little use in the arts.
Araenates of Copper. â€” Euchroite has a bright emerald-green color,
and contains 33 per cent, of arsenic acid, and 48 of oxyd of copper.
Occurs in modified rhombic prisms H=3-75. Gr=3'4. From Li-
bethen, in Hungary. Aphanesite is of a dark verdigris- green inclining
to blue, and also dark blue, Hss2-5â€” ^. Grs4-ld. It contains 30
per cent, of arsenic acid and 54 of oxyd of copper. From Cornwall.
Srinite has an emerald-green color, and occurs in mammilated coat-
ings. H=s4-5â€” 5. Gr=4*04. Contains 338 of arsenic acid and 594
of oxyd of copper. From Limerick, Ireland. Uroeonite varies from
sky-blue to virdigris-green. It occurs in rhombic prisms, sometimes
an inch broad. H=2*5. 6rs=2-8 â€” 29. Contaiofl 14 per cent, of
ai;senic acid, 49 of oxyd of copper. Olivenite presents olive-green to
brownish colors, and occurs in prismatic crystals or velvety coatings.
H=3. Gr=s4-2. Contains 36*7 per cent, of arsenic acid, to 56*4 of
oxyd of copper. Copper Mica is remarkable for its thin foliated or
mica-like structure. The color is emerald or grass-green. Ha=2.
Gr=2'55. It contains 21 per cent, of arsenic acid, 58 of oxyd of cop-
per, and 21 of water. From Cornwall and Hungary. Copper^Frotk
is another arsenate of a pale apple-green and verdigris green color. It
How does chrysocoUa differ from green malachite t Where is it
abundant in the U. States ? What is its use ?
COPYEX 0BC8. 885
ias a perfect cleayage. It contains 25 per cent, of aisenic aciil, 43*9
of ozyd of copper, 17*5 of water, with 13- 6 of carbonate of lirae. From
Hungary, Sibieria, the Tyrol, and Derbyshire. Condurrite has a brovni*
ish-black or blue color. From Cornwall. These different arsenates of
copper give an alUcaceous odor when heated on charcoal before the
Fhosphates of Copper. â€” Poeudo-malaehite occnn in very oblique
crystals, or massive and incrusting, and has an emerald or blackish-
green color. Hbs4'5â€” 5. Gr=s4'2. Contains 68 per cent, of ozyd
of copper. From near Bonn, on the Rhine, and also from Hungary.
Libethenite has a dark or olive-green color, and occurs in prismatic
crystals and masnve. Hss4. Grss3'6 â€” 38. Contains â‚¬4 per cent,
of ozyd of copper. From Hungary and Cornwall. Thrombolite is a
green phospate occurring massive ia Hungary. Containii 39 per cent*
of ozyd of copper. These phosphates give no fumes before the blowÂ«
pipe ; and have the reaction of phosphoric acid. /
-Cklorid of Copper, â€” Ataiamite. Color green to blackish-green.
Luster adamantine to vitreous. Streak apple*green. Translucent to
subtranslucent. Occurs in right rhombic prisms and rectangular octa-
hedrons, also massive. Consists of ozyd of copper 76*6, muriatic acid
10*6, water 12*8. Gives off fumes of muriatic acid before the blowpipe
and leaves a globule of copper. From the Atacama desert, between
Chili and Peru, and elsewhere in Chili ; also from Vesuvius and Sax-
ony. It is ground up in Chili, and sold aa a powder for letters undex
the name of arsenillo.
A SulphatO'chlorid of Copper has been observed in Cornwall, in blue
adcular crystals, apparently nezagonal.
Beaumontite of C. T. Jackson, is a hydrous crenato-silicate of cop-
per, containing 15*8 per cent, of crenic acid. It is bluish-green to
greenish- whi.e, and pulverulent when dry. From Chessy, France.
Vanadate of copper. Massive and foliated, or pulverulent ; folia
citron-yellow, pearly. From the Ural.
Buratite. A hydrous carbonate of coppef , zinc, and lime, occurring
in bluish radiating needles. Grs:d'2. From Cheesy, France ; the Al<^
tai mountaine ; and Tuscany.
Velvet Copper Ore. In velvety druaes or coating8> consisting of
short fine fibrous crystallization. Color fine smalt blue.
GENERAL REMARKS ON COPPER AND ITS ORES.
The metal copper has been known since the earliest periods. It is
obtained for the arts mostly from pyritous copper, the gray sulphurets,
and the carbonate ; also to some eztent from Uie black ozyd, and from
eolations of the sulphate, (page 281.)
Aesay ofOree. For the assay of copper ores by the dry way, tY^
following is a common method. A portion of the prepared ore, roasted
in a closed tube, will show by the garlic or sulphurous smell of the
fiimes, and by the depositions on the tube, whether arsenic, sulphur, or
both, be the mioeralizers. If this last is the case, which often happens,
100 or 1000 grains of the ore. are to be mized with me half of ita
weij^t of sawdust, then imbued with oil, and heated moderately in a
What is the mode of assaying copper ores in the dry way t
cneible, till all the araenicai fames are diflripated. The lesidaam, be-
ing cooled and triturated, is to be exposed in a shallow earthen dish,
made of refractory material, to a slow roasting heat, and stirred till the
sulphur and charcoal are burned away ; what remains being ground and
mixed with half its weight of calcined borax, or carbonate of soda, one-
twelfth its weight of lamp black, (finely pulverized charcoal will an-
swer,) and next, made into a dough with a few drops of oil, is then to
be pressed down into a crucible, which is to be covered with a luted
Ud, and subjected in a powerful air-furnace, first to a dull red heat, then
to vivid ignition tbrseven to twenty minutes. On cooling and breaking
the crucible, a button of metallic copper will be obtained, which may
be refined by melting again with borax in an open crucible. Its color
and malleability indicate pretty well the quality, as does its weight the
relative value, of the ore. It may be cupelled with lead to ascertain
if it contain silver or gold ; or it may be treated for the same purpose
with nitric acid.
If the blowpipe trial show no arsenic, the first calcination may be
â€¢mitted ; and if neither sulphur nor arsenic are present, a portion of the
pulverized ore should be dried and treated directly with borax, lamp-
black, and oil.
The ores of copper, (the sulphuret as well as the oxyds, carbonates,
&c.) may be reduced in the wet toay, by solution in strong nitric acid.
The solution, if made from the sulphuret, will contain sulphuric acid
and free sulphur, as well as all the bases, (iron, nickel, cobalt, lead, sil-
ver, &c.) which may have been present in the original ore. If ^ver
is present it will be found as a heavy white curdy precipitate, at the
bottom, if the nitric acid employed contained any hydrochloric acid ;
and if the addition of this acid to the solution occasions no such pre-
cipitate, no silver is present. If the solution is free from lead, anti-
mony, arsenic, and other metals precipitable by sulphnreted hydrogen,
the copper may be thrown down as sulphuret by means of a current of
this gas, the black precipitate, collected on a filter washed with water,
and redisBolved in aqua regia, largely diluted, and finally precipitated by
caustic potash, which throws down the black oxyd of copper. This
dried and weighed will yield the true value of the ore in metallic cop-
per. If only iron and copper are present, (which may be previously de-
termined by the blowpipe,) they may be separated fi-om their solutions
in nitric acid by ammonia, which throws down the iron as hydrated
peroxyd, but redissolves the copper precipitated by the first additions of
ammonia. The determination of the weight of the iron may then give
the amount of copper by the difference of weight, or the copper may
again be thrown down by potash as before directed.
Seduction of Oret. Copper ores are reduced in England in a rever*
beratory furnace, and the process consists in alternate calcinations and
fusions. The volatile ingredients are carried off by the calcinations,
and any metals in combination with the copper are oxydized. The
fusions serve to get rid of the various impurities, and finally bring out
the pure metal.
The calcinations or roastings are performed either in a furnace, or
by making piles in the open air. In this latter mode, which is in use
What is the mode of assaying copper ores in the wet way ? How
are copper ores reduced ? Describe the process of calcination 1
COPPER ORJS8. 287
on the continent of Earope, the ore, after being pounded and assorted,
is piled np in high pyramidal mounds, which mounds are covered with
mortar, sod, &c., and have a chimney at the center. Hemisphjcrical
cavities are dug on the upper sunace for the purpose of receiving the
solphur during the roasting, which arrives liquified at the surface. Thii
process lasts about six months. In England, at Swansea, where the
ores are carried for reduction, the calcinations are performed more rap-
Idly in a reverberatory furnace ; and this is especially necessary when
the ores do not contain a sufficient proportion of iron pyrites to furnish
enough sulphur to sustain the combustion. After calcination, the ore is
black and powdery. In the Swansea establishments, the calcined ore
is introduced into the furnace, (a reverberatory smaller than that used
for calcination,) and is spread over the bottom, I cwt. at a time. The
heat is raised, and the furnace closed. When fusion has taken place,
the liquid mass is well rabbled or stirred, so as to allow of the complete
separation of the slags from the metal ; afterwards the slags are skimmed
ofT. Then a second charge is added, and after a similar process, a
third charge, if the furnace is deep enough to receive it without the
metal's flowing from the door. After the last charge is reduced also,
the tap-hole is opened, and the metal flows out into water, where it is
granulated. The slags if not free from metal are again returned to the
furnace, when other charges are put in. This granulated metal is
usually about one-third copper ; it contains sulphur, copper, and iron.
This coarse metal is next calcined, just as the ore was first calcined ;
by which the iron is oxydized. The charge remains in the furnace 24
hours, and is repeatedly stirred and turned.
It is then transferred to the furnace for melting, and there melted
along with some dags from the previous fusion. The sulphur reduces
any oxyd and the whole fuses down. The slags are skimmed off and
the furnace tapped : the metal is again drawn off into water. In this
state it contains about 60 per cent, of copper, and it is called fine
metal. The fine metal is then calcined like the coarse metal ; and next
it is melted as before. It results in a coarse copper containing 80 to 90
per cent, of pure metal.
The coarse copper is then roasted in the melting furnace ; the air
drawing in large quantities over the copper in incipient fusion, oxydizes
the iron and the volatile substances are driven off. The metal is fused
toward the end of the operation, which is continued fi-om 12 to 24
hours, and is then tapped into sand beds. The pigs formed are cov-
ered with black blisters and they are cellular within. The copper is
then remelted in a melting furnace ; it is heated slowly to allow of any
farther oxydizing that may be necessary. The slag is removed and the
metal is examined from time to time, by taking out some of it, and
when it is in the right condition, it is next subjected to the process of
toughening. It is now brittle, of a deep red color inclining to purple,
with an open grain and a crystalline structure ; the copper in this state
iS what is termed dry. The surface of the melted metal is first cov-
ered with charcoal ; a pole, commonly of birch, is held in the liquid
matter, causing considerable ebullition ; and this poling is continued,
with occasional additions of charcoal, till it is found in the assays taken
What are the several steps in reduction 7
out that tho cryBtalline grain has disappeared, and the copper when cut
through has a silky polished appearonce, and the color is light red.
It is then ladeled oat into moulds, usually 12 indhes in width by 18 long.
Lead 'is sometimes added in the purification, to aid by its own oxyda*
tion in the ozydation of the iron present.
The process of melting copper on the continent is done by blast fiir*
naces instead of the reverberatory, and they are .said to be more eco-
nomical in fuel, and produce a less waste of copper in the slags. This
mode is used at the works at Boston, while the Swansea mode has
been adopted at the Baltimore furnaces, Maryland. At the Ha'ford
works. South Wales, a furnace of three tiers of hearths has been intro-
duced, which answers the double purpose of calcination and fusion at
the same time.
Galvanism has been turned to account in the reduction of copper
ores. The ore is converted into a sulphate by roasting with the free
access of the atmosphere. From this sulphate the copper is deposited
in a pure state by galvanic decomposition. See on this subject Ameri-
can Journal of Science, ii ser., volume iv, p. 276, or Franklin Journal,
volume zi, p. 128.
Copper Mines. The principal mines of copper in the world are those
of Cornwall and Devon, England ; of the island of Cuba ; of Copiapo,
and other places in Chili ; Chessy, near Lyons, in France ; in the
Enegebirge, Saxony ; at Eisleben and Sangerhaosen, in Prussia ; at
Goslar, in the Lower Hartz ; at Schemmitz, Kremnitz, Kapnik, and
the Bannat, in Hungary ; at Fahlun, in Sweden ; at Turinsk and Nisch-
ni-Tagilsk, and other places in the Urals ; also in China and Japan.
Lately extensive mines have been opened in Southern Australia.
In the United States, considerable quantities have been raised from
the mines of New Jersey, and those of Simsbury, Conn. At Bristol,
Conn., is a fine vein of vitreous copper, now under exploration. Straf-
ford, Vermont, affords some tons of pyritous copper at the present time
for the Boston furnace.
The most extensive deposits are those of Northern Michigan and
Wisconsin. The Michigan mines are vertical veins mostly in the trap