47 
Fig. 13—16. Red or Ruby Silver Ore, Silver-Blende. 
The primary form is a rhombohedron, similar to that of 
calcite, of 108° 18', which usually occurs with truncation of 
the vertical and basal edges, as Fig. 15, or in combination 
with the scalenohedron, as Fig. 16 ; it is also found in hexa¬ 
gonal prisms, as Fig. 14, or in combination with several 
rhombohedrons, with a lenticular and drusy arrangement, 
as Fig. 13, sometimes also in compact or foliated masses. 
Hardness 2’5—3, specific gravity 5 - 53—5’85. Lustre 
metallic to lustrous. Blackish-grey passing into cochineal 
and carmine-red, with crimson streak; friable. We dis¬ 
tinguish between a dark and a light red silver ore ; the 
former is an antimonial silver blende, a combination of three 
equivalents of simple sulphuret of silver and one equiva- 
/ /// 
lent of sesqui-sulphuret of antimony (Ag 3 Bb), containing 
58‘949 of silver, giving on the charcoal an ash of antimony 
and sulphur, and leaving as residue a grain of silver. It 
is found in remarkably fine crystals, as Fig. 14, at Freiberg 
and Joachimsthal, also in the Hartz and in Hungary, as 
well as in very considerable quantity at Zacatecas in 
Mexico. The light-red silver ore is an arsenic-silver-blende, 
translucent with a red colour, of adamantine lustre and a 
light-red streak. The composition is the same as that of 
the former, except that the sulphuret of antimony is re- 
f nr 
placed by the sulphuret of arsenic, thus = Ag 3 As. On the 
charcoal it gives strong arsenical vapours, and leaves a grain 
of silver; in the retort the sulphuret of arsenic is sublimed, 
and the sulphuret of silver remains behind. It occurs in re¬ 
markable quantities at Andreasberg in the Hartz, also in the 
Erzgebirge and the Schwarzwald, sometimes along with the 
dark-red ore. Fig. 13 represents a druse from Andreasberg. 
There are also arsenic and antimony silver blendes, 
and still other similar combinations. The xantholcon , of 
444 specific gravity, is one of these changed red- silver 
ores of orange-yellow streak, with 64 per cent, of silver, 
which is found at the Himmelsfiirst mines at Freiberg, 
and crystallises in rhombohedral tables. 
Fire-blende is a foliated, pearly lustrous, orange-yellow, 
silver-blende, which contains 62*3 of silver, together with 
antimony and sulphur. It is found as a rarity at the 
Kurprinz mines at Freiberg, and at Andreasberg. 
Miargyrite is oblique rhombic, of adamantine to 
metallic lustre, of 2 - 0 hardness, and 5'2—-5'4 specific 
gravity, opaque, and consists of equal proportions of simple 
sulphuret of silver and sesqui-sulphuret of antimony = 
f nr 
Ag &b; the amount of silver contained is 36’40. It is 
found at Braunsdorf in Saxony. 
Chloride of Silver, Horn-Silver, Kerate, 
Crystallises in cubes of indistinct foliated structure, some¬ 
times with truncation of the angles and edges. It is 
found, however, more frequently disseminated as a crust-like 
coating, or in compact masses. When fresh it presents a 
bright adamantine lustre, and is transparent; in the light it 
becomes pearl-grey, violet, blackish, and opaque. Very soft 
and malleable, so that it may be forged and cut. Hardness 
1*0—1*5, specific gravity 5’5 —5‘6. It is simple chloride 
of silver, Ag Cl, composed of 76 of silver and 24 of chlo¬ 
rine. It melts readily before the blow-pipe, gives off 
chlorine vapours, and leaves as residue a grain of silver. 
When fused with protoxide of copper, and salt of phos¬ 
phorus, the bright blue flame of chloride of copper is 
produced. In nitric acid it is insoluble, and only partially 
soluble in caustic ammonia. Is found in remarkably fine 
crystals at the Markus Reling mines at Schneeberg in 
Saxony, and at St. Jago in Chili. It was at one time 
found in compact masses at Schneeberg, in the Royal 
Collection of Minerals at Dresden, there is a fragment of 
about 7 pounds weight, which is said to have been found 
below the church of Schneeberg, exactly under where the 
high altar now stands. 
The so-called gosling-green silver is a chloride of silver 
mingled with clay and earthy cobalt, which occurs at 
Schemnitz in Hungary, and at Andreasberg in the Hartz 
mountains. 
Bromide of silver crystallises in cubes, and is of a 
pearl-grey colour, passing into siskin-green, unchanged by 
light; it consists of simple bromide of silver, Ag Br. Is 
found in the district of Plateros in Mexico ; and chloro- 
bromide of silver occurs at Copiapo in Chili. Iodide of 
silver is found in Mexico and Chili, in thin translucent 
leaves, of adamantine to resinous lustre, pearl-grey, malle¬ 
able and flexible, of 1’5 hardness, and is simple iodide of 
silver, containing 77 *4 of silver, and 22’6 of iodine. It 
colours flame purple-red, and when heated with a 
little hydrochloric acid in a test-tube, gives off vapours of 
iodine. 
Seleniuret of silver, which crystallises in hexagonal 
. prisms. Is found at Tasco in Mexico, as a double sele¬ 
niuret of silver ; it has a lead-grey colour, with slight 
metallic lustre, and is malleable. It is dense and iron- 
grey, passing into reddish, at Tilkerode in the Hartz; 
and is here a simple seleniuret of silver, rendered 
impure by seleniuret of lead, and contains 65’56 per 
cent, of silver. 
II. COMMON METALS. 
PLATE XV. 
Fig. 1—-5.—Quicksilver, Mercury. 
Mercury is a simple metal, which is liquid at ordi¬ 
nary temperatures. It is scantily distributed in nature, 
and is always found only in the igneous and older stra¬ 
tified rocks, either in veins or beds. It occurs native, in 
combination with silver, as an amalgam, mineralised by 
sulphur as cinnabar, as well as combined with chlorine and 
iodine, and also as an element of some fossil ores. The 
principal ore, however, is cinnabar, from which it can also 
be extracted with facility by simple burning; from its 
being liquid, and having only a slight affinity for oxygen, 
it approaches in this respect the noble metals. 
