copper, the latter ingredient oflen amounting to 10 per cent*
It is also alloyed with gold, as mentioned under that metal.
A. bismuth silver from Copiapo, S. A«, contained 16 per cent,
of bismuth.
What sariace may a grain of gold be made to covert How much
pure gold is there in the American eagle 1 What is the use of the
term carat ] What is the condition of silver in nature 7 Deecribe na-
tive silver.
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820 XIETALS.
Before the blowpipe it fuses easily and affords a globcde
which becomes angular on cooling. DissoWes in nitric acid,
from which it is precipitated bj putting in a clean piece of
copper.
JHf, Distinguished by being malleable ; from bismuth
and other white native metals b/ affording no fumes before
the blowpipe ; by affording a solution with muriatic acid*
which becomes black on exposure*
0&9. Native silver occurs in masses and string-like ar-
borescences, penetrating rocks, and is found in igneous rocks
and in sedimentary strata, in the vicinity of dikes of trap
and porphyry.
The mines of Norway, at Kongsberg, formerly afforded
magnificent specimens of native silver, but they are now
mostly under water. One specimen from this locality, at
Copenhagen, weighs five hundred pounds. Other European
localities are in Saxony, Bohemia, the Hartz, Uungaiy,
Dauphiny. Peru and Mexico also afford native silver* A
Mexican specimen from Batopilas, weighed when obtained,
400 pounds ; and one from Southern Peru, (mines of Huan-
tajaya,) weighed over 8 cwt. In the United States, elegant
specimens are associated with the native copper of Lake Su«
perior. The silver generally penetrates the copper in masses
and strings, and is very nearly pure, notwithstanding the
copper about it.
Much of the galena of the west contains a very small per
centage of silver, and that of Monroe, Conn., yields nearly 8
per cent.
Native silver has also been observed near the Sing Sing
state prison ; at the Bridgewater copper mines, N. J. ; and
in handsome specimens at King's mine, Davidson county,
North Carolina.
TJsesm The uses of silver are, for the manufacture of va-
rious articles of luxury, - for plating other metals, for philo-
sophical instruments, tor coinage, and also various purposes
in the arts. For coins, it is alloyed in this country with
copper, and is thus rendered harder and more durable ; 1000
parts of the coin contains 100 parts of copper. When this
alloy is boiled with a solution of cream of tartar and sea-
salt, or scrubbed with water of ammonia, the superficial
How is native silver distinguished ? How does it occar and in what
rocks \ Where does silver occur in the U. States, and how ? What
are the uses of silver ?
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SII.VBB ones. 32]
partieles of copper are removed, and (. surfiice of fine sihrer
is left. Silver is much less malleable than gold, and can-
not be beaten into unbroken leaves less than 160,000th
part of an inch thick.
In expressing in the arts the puiitj of silver, if absolutely
pure, it is said to be silver of 12 pennyweights ; if it con-
tain 1^ of its weight of alloy it is called silver of 11 penny-
weights ; if 2-12Ui8 be alloy, it b called silver of 10 penny-
weights, and so on.
viTBsous siLTBR. — Stdpkuret of Silver.
Monometric. In dodecahedrons more or less modified.
Fig. 22a, page 30, and also other modifications* Cleavage
sometimes apparent parallel to the &ces of
the dodeci^edron* Also reticulated and mas-
sive.
Luster metallic. Color and streak black*
ish lead-gray ; streak shining. Brittle. H =
»-.2'5. Gr=:7-19— 7-4.
Composition: when pure, silver 87*04, sulphur 12*00.
Before the blowpipe it intumesces, gives off an odor of sul-
phur, and finally afibrds a globule of silver. Soluble in di-
lute nitric acid.
Dif, Resembled some ores of copper and lead, and other
ores of silver, but is distinguished as a sulphuret by giving
the odor of sulphur before the blowpipe, and as an ore of
silver by affording a globule of this metal, by heat alone.
Its specific gravity is much higher than any copper ores.
Ohs. This important ore of silver occurs in Europe,
principally at Annaberg, Joachimstahl, and other mines of
the Er^ebirge ; at Schemnitz, and Kremnitz, in Hungary,
and at Freibei^g in Saxony. It is a common ore at the Mex-
ican silver mines, and also in the mines of South America.
A mass of sulphuret of silver, is stated by Troost, to have
been found in Sparta, Tennessee. It also occurs with na-
tive silver and copper in Northern Michigan.
Uses. This is a common and highly valuable ore of sil-
ver.
Besides this ealphuret of sUver there are two others, which contain
also salpharet of iron or copper.
What 18 the appearance of yitreons silver ? What Ji its composition t
What is its value ? How is it distinguished T
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8*2S MBTALS.
StfwmeyeriU. This m a Bteel-gray Milphurei of nlver and copper,
containing 52 per cent, of siWer. Gr86'26. Before Uie blowpipe it
fiises and gives an odor of sulphur ; but a silver globule is not obiained
except by cupellation with lead. A solution in nitric acid covers a
plate of iron with copper, and a plate of copper with silver indicating
the copper and silver present. From Perm, Siberia, and Europe.
Sttmbergite. A sulphuret of silver and iron containing 33 per cent,
of silver. It is a highly foliated ore resembling graphite, and like it
leaving a tracing on paper ; the thin lamine are flexible ^and may be
smoothed out by the nail. Luster metallic, color pinchbeck brown.
Streak black. It affords the odor of sulphur and a globule covered
with silver on charcoal, before the blowipe. With borax a globule of
â– ilver is obtained. From Joachimstahl, in Bohemia.
BRITTLE SILVER ORB. — Sulpkuret oJ[ SUv&r and Antimony*
Tri metric. In modified right rhombic prisms. M : Mss
115° 39'. No perfect cleavage. Often in compound ciys-
tals. Also massive.
Luster metallic ; streak and color iron-black. H = 2-— 2*5.
Gr=6-27.
Composition : Sulphur 16*4, antimony 14*7, silver 68*5^
copper 0*6. Before the blowpipe it gives an odor of sulphur
and also fumes of antimony, and yields a dark metallic glob-
ule from which silver may be obtained by the addition of
soda. Soluble in dilute nitric acid, and the solution indi*
cates the presence of silver by silvering a plate of copper.
Dif. The black color of this ore distinguishes it from
the preceding ; and more decidedly the fumes of antimony
given off before the blowpipe. By the trial with nitric acid
as well as by soda and the blowpipe, it is ascertained to be
an ore of silver.
Obs, It occurs with other silver ores at Freiberg, Schnee-
berg, and Johamigeorgenstadt, in Saxony ; also in Bohe-
mia, and Hungary. It is an abundant ore in Chili, Perut
and Mexico. It is sometimes called black silver.
An antimonial sulphuret of silver is said to occur with
native silver and native copper, at the copper mines in
Michigan.
Uses. This is a very important ore for obtaining silver,
especially at the South American mines.
Besides this there are other antimonial, and also arsenical and sele*
nlferoQS ores of silver.
What is the composition of brittle silver ore ] its color and appear*
ance ? For what is it valued ?
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KILVEK ORES. 323
AnHmonial SUver, consists simply of silver and aDtimoiiy, (84 parts
io 160 and has nearly a tin>white color. Grs=9 4 — ^9'8. Before the
blowpipe gray iiimes of antimony pass of!^ leaving finally a globule of
silver.
Polybasiie is near brittle silver ore in color, specific gravity, and com-
position, but contains some arsenic and copper, with 643 per cent, of
silver. The crystals are usually in tabular hexagonal prisms, without
cleavage. From Mexico and Peru.
Miargyrite is an antimonial sulphuret of silver, containing but 36'5
per cent, of silver, and having a dark cherry-red Hreak, though iron*
hiack in color. Before the blowpipe gives off fumes of antimony and
an odor of sulphur ; and with soda, a globule is lefi which finally yields
a button of pure silver.
Dark Red Silver Ore, and Light Red Silver Ore, are two allied ores
rhombohedral in their crystals. The former contains silver (59 per
cent.,) antimony, and sulphur, and has a color varying fi*om black to
cochineal red, a metallic adamantine luster, and a red streak, Hs2'5.
Gr«5-7— 59.
The latter consists of silver, (64*7 per cent.) arsenic, and sulphur.
Its color and streak are cochineal red. Hs=£3 — ^S*5. Grss5-4 —
5*6. Before the blowpipe these species fuse easily, give off fumes, one
of antimony, the other of arsenic ; and finally a globule of silver is ob-
tained. They are abundant ores in Mexico, and occur also in Saxony,
Hungary, and Bohemia. These ores have been called ruby silver.
Eucairite is a eeleniferous ore of silver and copper occurring in black
metallic films. It gives before the blowpipe fumes of selenium, having
an odor like that of deca3ring horse-radish. From Sweden. Another
seleniferous ore, from the Hartz, called selentUver, contains silver
and selenium, with a little lead, and crystallizes in cubes.
Telluric Silver is a Russian ore, of a steel-gray color, containing
silver 62*3, and tellurium 36*9. Another variety contains 18 per fbnt.
of gold. 6r=8-3 - 8-8. With soda, silver is obtained.
Carbonate of Silver is a rare ore of an ash-gray color, consisting of
carbonic acid and oxyd of silver. It is easily reduced before the blow-
pipe.
HORN SILVER. CfUorid of SUvCT,
Monometric. In cubes, with no distinct cleavage. Also
massive, and rarely columnar ; often incrusting.
Color gray, passing into green and blue, and looking
somewhat like horn or wax. Luster resinous, passing into
adamantine. Streak shining. Translucent to nearly opaque.
Cuts like wax or horn.
Composition: when pure, silver 75*3, chlorine 24'7.
Fuses in the flame of a candle, and emits acrid fumes. Af-
lords silver easily on charcoal. The surface of a plate of
iron rubbed with it is silvered.
Describe horn silver. Of what does it consist 7
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824 MBTAI.B.
Ob»» A very common ore and extensively worked in the
mines of South America and Mexico, where it occurs with
native silver. It also occurs at the mines of Saxony, Sibe-
ria, Norway, the Hartz, and in Cornwall.
Jodie Silver, Bromie Silver. Silver also occuns in nature united
with iodine and bromine. These rare ores occur with the preceding
in Mexico, and the latter in Chile, and at Huelgoet, in Brittany.
Chenocoprolite, {ganeekothig-erx of the Geimans.) Mammillary, of a
fellow or pale green color ; luster resinous. Yields silver and allia-
oeous fiunes before the blowpipe, and is supposed to be an arsenate of
silver and iron.
REMARKS ON SILVER AND ITS ORES.
The ores from which the silver of commerce is mosdy obtained are
the viireave silver, brittle or black eilver ore, red eUver ore and kom
oilver, in addition to native silver. Besides these, silver is obtained in
Urge quantities from galena, (lead ore,) and from different ores of cop-
per : and some galenas are so rich in silver that the lead is neglected
for the more precious metal. This metal occurs in rocks of various
ages, in gneiss, and allied rocks, in porphyry, trsp, sandstone, lime-
stone, and shales ; and the sandstone and shales may be as recent as the
middle secondary, as is the case in Prussia, and probably also in our
own Michigan mining region. The silver ores are associated often
with ores of lead, zinc, copper, cobalt, and antimony, and the usual
gangue is calc spar or quartz, with frequently fluor spar, pearl spar, or
heavy spar.
The silver of South America is derived principally from the horn sil-
ver,**brittle silver ores, including arseniuretted silver ore, vitreous silver
ore, and native silver. Those of Mejico are of nearly the same charac-
ter. Besides, there are earthy ores called eoloradoe, and in Fera pacos,
which are mostly earthy oxyd of iron, with a little disseminated silver ;
they are found near the surface where the rock has undergone partial
decomposition. The sulphurets of lead, iron, and copper, of the mining
regions, generally contain silver, and are also worked.
The mines of Mexico are most abundant between 18^ and 24^ north
latitude, on the back or sides of the Cordilleras and especially the west
side ; and the principal are those of the districts of Guanaxuato, Zaca-
tecas, Fresnilk), Sombrerete, Catorce, Oaxaca, Pachuca, Real del Monte,
Moran, and Pasco. The veins traverse very different rocks in these
regions. The vein of Guanaxuato, the most productive in Mexico, in-
tersects argillaceous and chloritic 49hale, and porphyry ; it affords one-
fourth of all the Mexican silver. The Valencian mine is the richest in
Guanaxuato, and has yielded for many ye%rs, from one to two millions
of dollars annually. In the district of Zacatecas the veins are in gray-
Where is horn silver a common .ore ? From what ores is the silver
of commerce mostly obtained ? How do they occur ? What are the
common ores of South America ?
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8ILVBR amsft. M5
wmcke. In Somlirerete they oecur in limeitcme ; and there are ezten«
eive veins of the antimonial sulphuret, one of which gave in ox months
700,000 marcs, (418,000 lbs. troy) of silver. The Pachcca, Real del
Monte, and Moran districts, are near one another. Four great parallel
veins transverse these districts, through a decomposed porphyry. From
the vein Biscaina, in Real del Monte, (5,000,000 were realized by the
Count de Regla, in twelve years.
In South America the Chilian mines are on the western slope of the
Cordilleras, and are connected mostly with stratified deposits, of a shaly,
sandstone, or conglomerate, character, or with their intersections with
porphyries. The chlorids and native-amalgama are foand in regions
more towards the coast, while the sulphurets and antimonial ores
abound nearer the Cordilleras. The mountains north of the valley of
Huasco contain the richest silver mines of Chili. The mines of Mt.
Chanarcillo produces at the present time more than 80,000 marcs of
silver per year. The veins abound in horn sifver, and begin to yield
arsenio-sulphurets at a depth of about 500 feet. The mines of Punta
Brava, in Copiapo, which are nearer the Cordilleras, afibrd the arseni-
uretted ores.
In Peru, the principal mines are in the districts of Pssco, Chota, and
Hnantaya. Those of Pasco are 15,700 feet above the sea, while those
of Hnantaya are in a low desert plain, near the port of Yquique, in the
southern part of Peru. The ores afforded are the same as in Chiti.
The mines of Hnantaya are noted for the large masses of native silver
they have afforded.
The Potosi mines in Buenos Ayres, occur in a mountain of argillac
ceous shale, whose summit is covered by a bed of argillaceous porphyry.
The ore is the red silver, the vitreous qre along with native silver. It has
been estimated that they have afforded since their discovery (l^OO,-
000,000. These mines have diminished in value, though they still rank
next to those of Guanazuato.
In Europe the principal mines are those of Spain, of Kongsberg in
Norway, of Saxony, the Hartz, Austria, and Russia. The mines of
Kongsberg occur in gneiss and hornblende slate, in a gangue of cale
spar. They were especially rich in native silver, but are now nearly
exhausted. The silver of Spain is obtained mostly from galena, and
principally in the Sierra Aknagrera in Grenada.
The mines of Saxony occur mostly in gneiss, in the vicinity of Frey«
berg, Ehrenfriedensdorf, Johangeorgenstadt, Annaberg and Schneeberg.
The ores of the Hartz are mostly argentiferous copper pyrites and
galena, yet the red silver, vitreous silver ore, brittle silveV ore, and ar*
senical silver, occur, especially at Andreaskreutz, and the mines of that
vicinity. The rock intersected by the deposits is mostly an argillace-
ous shale. Carbonate of lime is the usual gangue, though it is some-
times quartz
In the Tyiol, Austria, sulphuret of silver, argentiferous gray copper,
and mispickel occur in a gangue of quartz, in argillaceous schist. The
Hungarian mines at Schemmitz and Kremnitz, occur in syenite and
hornblende porphyry, in a gangue of quartz, often with calc spar or
heavy spar, and sometimes fluor. The ores are sulphuret of silver
Where are the principal mines in Europe 7
28
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MBTALi.
(imy copper, galena, blende, pyritoua c<9per and iron ; and the galena,
and copper ores are argentiferooB.
The Russian mines of Kolyvan in the Altai, and of Nertchinsk in the
Daooha mounuins, Siberia, (east of Lake Baikal,) are increasing in
valne, and yield annually 76,500 marcs (47,800 troy pounds) of silver.
The Daouria mines afford an argentiferous galena which is worked for
its silver. It occurs in a crystalline limestone. The silver ores of the
Altai occur in Silurian schists in the vicinity of porphyry, which con-
tain besides silver ores, gold, copper, and lead ores.
In England argentiferous galena is worked for its silver. 40,000
tons of the ore were reduced in 1837, one half of which Contained 6 to
8} oz. of silver to the ton of lead, and the other half only 4 to 5 oz. of
â– ilver.
In the United States, the Washington silver mine, in Davidson coun-
ty, N. Carolina, had afforded up to 1845, 30,000 dollars of silver. The
native silver of Michigan is associated with copper in trap and sand-
stone. These mines promise to be highly productive.
The silver mines of the woiid have been estimated to yield at the
present time |02O,OOO,OOO annually.
The annual product of the several countries of Europe is nearly aa
follows ; —
pounds troy. pounds troy.
British Islea. 7,500 Saxony, the Hartz, and } 73 aqa
other parts of Germany, ) '^
Belgium, 440
Piedmont, Switzerland and > , cer^
Saxony, ) '^'^^
making in ail 298,150 troy pounds, or about 4,500,000 dollars annually.
With the sum from Russia, about 730,000 dollars, it becomes 5,230,000
a year. This is small compared with the amount from America, which
at the beginning of the present century equalled 2,100,000 pounds, or
31 i millions of dollars, nearly six times the above sum ; and it is prob-
able that these mines will again yield this amount when properly
worked. The whole sum from Russia, Europe, and America, makes
nearly 2,000/)00 poimds avoirdupois.
The common modes o( reducing silver ores in the large way arc two ;
by amalgamation, and by tmelting. Both mercury and lead have a
strong affinity for silver, and these reducing processes are based on this
fact. In amalgamation, the silver ore is brought to the state of a chlo-
rid by a mixtpe of the powdered ore (or " schlich,") with about ten per
cent, of common salt ; the chlorid is reduced by means of salts or sul-
phurets of iron, or metallic iron in filings, and at the same time mer-
cury which has been added, combines with the liberated silver, and thus
separates it in the condition of an amalgam, (a compound of mercury
and silver.) The mixture of salt and " schlich" requires several days to
become complete. Heat is employed at the Saxon mines, but not at
those of Mexico, where the climate is tropical. After the mercury is
put in, (6 or 8 parts to 1 of silver,) the mixture is kept in constant agi-
Where are the Russian mines] What is the yield of the silver
mines of the world 7 What was afforded by South America at the be-
ginning of this century 7 Describe the process of amalgamation.
France, 4,150
Austria, 63,000
Sweden and Norway, 13,000
Spain. 130/K)0
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SILVER ORES.
827
tation until the process is finiflhed. In the beet Arrangements, as in
Saxony, this agitation is performed in revolving barrels, and the result
is accomplished in a few hours ; but in Mexico it is effected by the
treading of mules or oxen, and requires two or three weeks or more.
The amalgam, separated from the muddy mass, by a current of water
or washing, is then filtered of the excess of mercury ; as a last step it is
subjected to heat in a distilling furnace, by which the silver is left be-
hind, the mercury passing off in a state of vapor to be condensed in a
condensing chamber or receptacle. The loss of mercury by the pro-
cess is often large.
In case of the ordinary sulphurets and arseniurets of silver, or the
chlorid, in Mexico and South America, the poorer ores are first fused
with a flux, and the result, (called the *' matt'') is then roasted to expel
the sulphur ; afterwards it is mixed with better ores, again fused, and
on cooling, again roasted. This fusion and roasting is again repeated
with the best ores. The result from this fusion is next mixed thorough-
ly with melted lead ; the lead separates the silver ; and the impurities
which float on the surface, are removed in plates as a crust cools, to be
igain melted with new ores, as the slag is apt to contain some of tfae
ifllver.
When the argentiferous galena is the ore, it is reduced by roasting in
% reverberatory furnace in the ordinary way for lead ore ; the resulting
/ead contains also the silver.
The accompanying sketch represents the essential characters of a
feverberatory furnace. It is a transverse section, a is the grate on
which the fire is made,
and from which the flame
proceeds through the hor-
izontal chamber or gen-
eral cavity of the furnace,
(usually very low,) to
the flue at e. b is the
sole of the hearth, for re-
receiving the ore or as-
say, having an elliptical or circular form according to the shape of
the furnace ; c is the fire bridge, separating the fire from the sole ;
i2 is the arched roof. The flame plays horizontally over the charge of
ore, and as the air may be made to pass freely with it, we may have in
such a furnace a combined effect derived from the heat and the pres-
ence of the atmosphere ; the ore,' or its metal, if capable of uniting with
the oxygen of the atmosphere, may be oxydated by the process, pre-
cisely as in the outer or oxydating flame of the blowpipe. In an or-
dinary blast furnace, (page ^3,) the ore and its flux are confined from
the atmosphere, (except the air that enters with the blast,) and the re-
sult is the reduction of an ore or its deoxydation, as in the inner or re-
ducing flame of the blowpipe. This latter effect may in many cases
be obtained also with a reverberatory furnace, when the atmosphere is
excluded except what is essential to feeding the fire.
In the reverberatory furnace, there is a small door near the fire-grate,
«, for putting in fuel. There is also an opening either at top, or on the
Describe a reverberatory furnace.
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928 MBTAL8.
side, for introducing the chnrge ; also there may he one or mon doors
on each aide for working the charge while exposed to the heat. There
may also be a tap hole for drawing off the reduced metal into one or
more pota attached for the purpose ; another in some cases for the es-
cape of slag as in cupelhition, and where there is a vaporizable ingre-
dient to be condensed, one or two fines leading to a condensing cham-
ber. In large establishments several of these reverberatoiy furnaces
connect with a single chimney. They are actually like large elliptical
or circular ovens, of brick or atone, commnnicating with a common
flue. ^
In reveiheratory furnaces adapted for melting metals, the hearth is
a gently inclined plane, doping to a spot towards one end, in order that
the fused metal may flow down together and be convenient for drawing
off. For many other purposes, the 90U is flat, and the depth is greater
than in the above figure.
To separate the silver firom the lead, the lead is heated in a reverbe-
ratory furnace, the hearth of which is covered with wood ashes and
clay, so as to give it the nature of a cupel. The air received through
an aperture on one side, passes over the metal in fusion, m a constant
current, ozydizing it and changing it to litharge, which is from time to
time drawn out ; finally the lead is thus removed, and the silver remains
nearly pure. The completion of the process is known by the metal be-
coming brilliant. It is again subjected to another similar operation, and
thus rendered quite pure. The litharge from the latter part of the pro-
cess is also subjected to another operation for the silver it nsnaUy con-
tains.
According to Pattinson> new process, adopted in £kigland, the silver
is separated by melting the lead, and, as it begins to cool, straining out
the crystals with an iron strainer. The portion left behind contains
nearly all the silver. This is several times repeated, each time the re«