52 
and silica. Until now it has only been found in the 
Kirghese Steppes, west from Altai in Siberia, and one of 
its names, achirite , is derived from Achir Mamed, a Buch- 
arian merchant, who first brought it to Europe. 
Fig. 18— 22. — Arseniates op Copper. 
The compounds of arsenic with oxide of copper are 
exceedingly numerous, a complete series of them being 
known, and many of them also contain arseniate of iron. 
They occur only sparingly, however, and serve rather as an 
ornament of mineralogical collections than as an object of 
any great value as an ore. 
Liroconite, of a verdigris-green to a sky-blue colour, 
crystallising in right rhombic prisms, sometimes in second¬ 
ary tables (Fig. 19) is found at Huels, Gorland, and Unity, 
in Grwennap, in Cornwall. Fig. 20 represents an isolated 
crystal. 
Euchroite, emerald-green, usually aggregated in rhombic 
octahedrons, as in Fig. 18, is found in quartzose mica 
slate at Libethen, in Hungary. 
Olivenite , Fig. 21, dark olive-green, in Cornwall, 
Devonshire, and Cumberland. The wood arseniate, with 
soft, velvet surface, and greenish-grey appearance, is a 
variety of olivenite, and is also found in Cornwall. 
Copper Mica, or Chalcophyllite, in blue-green, pearly- 
lustrous foliated masses, or rhombohedral tables, like Fig. 
22, from the same place. 
Fig. 23.—Blue Vitriol, Sulphate of Copper, 
Cyanosite. 
Crystallises in oblique rhomboidal prisms, sometimes 
with truncation of the obtuse lateral edges, like Fig 23, 
and of the acute basal edges and solid angles; sky-blue, 
of vitreous lustre, translucent, brittle, hardness 2*5, specific 
gravity 2*2—2*3. Crystals are very rare, more frequently 
it occurs in crystalline encrustations, or stalactitic, gene¬ 
rally as a product of decomposition of copper pyrites in 
old mines, as, for example, in Salzburg and Rammelsberg, 
in Cornwall, Anglesea, and Wicklow. The copper is ex¬ 
tracted from it by laying iron bars in the pits, and on the 
iron being dissolved, it is replaced by a deposit of copper. 
At Wicklow, 500 tons of iron having been thus intro¬ 
duced, the iron was dissolved in a year, and every ton of 
iron yielded from a ton and a-half to two tons of reddish 
mud, which was principally oxide of copper, each ton 
yielding about 16 cwt. of pure metallic copper. Blue 
vitriol is manufactured mostly from old copper and the 
residue of smelting. The composition is simple sulphate 
of copper, with 5 eq. of water = Cu S + 5 H. Blue 
vitriol is used for many purposes, in colouring calico and 
other stuff printing, in galvano-plastic operations, and in 
medicine. 
Brochantite is basic sulphate of copper, with 3 eq. of 
water, and crystallises in right rhombic prisms, which are 
emerald-green, of vitreous lustre, and transparent. It oc¬ 
curs at Retzbanya and Libethen, in Hungary, at Roughten- 
gill in Cumberland, and at Katherinenberg in Siberia. 
Atacamite, or chloride of copper, crystallises in right 
rhombic prisms and needles; more frequently it is found with 
cuprite in crystalline-granular aggregations, or foliated as in 
Chili and Peru, or disseminated, as in the lavas of Vesuvius 
and Etna. It is chloride of copper with 3 eq. of hydrous 
oxide of copper, of 2*5 hardness, and 4*43 specific gravity, 
emerald-green passing into olive-green, slightly to vitreo- 
lustrous, translucent, and colours the flame of the blow-pipe 
a magnificent blue, and at last green. When reduced to 
powder it is sold in Chili under the name of arsenillo, as 
a green sand for sprinkling over newly-written letters. 
PLATE XVII. 
Fig. 1—4.—Nickel Ores. 
Nickel is sparingly distributed in nature, and is prin¬ 
cipally limited to veins and lodes of the older rocks. It is 
not found native, but usually in combination with sulphur, 
arsenic, cobalt, or oxygen. Most of the ores have a 
metallic appearance, and when heated yield a yellowish- 
green oxide, which, with borax, gives a brownish-red glass, 
and which, on the addition of a salt of potash, becomes 
blue; when held in the reducing flame, however, metallic 
nickel is separated in silver-white spangles, which follow the 
magnet on being washed out, nickel showing the highest 
degree of magnetism with the exception of iron. With 
cyanide of potassium the assay yields a loose, infusible, 
spongy grain of metallic nickel, which is likewise attracted 
by the magnet. If there is cobalt in the ore, the assay 
gives a blue pearl with borax. Most of the metallic nickel 
is obtained from the various arsenic compounds, and also 
from the residue which, under the name of speiss, is obtained 
from the preparation of smalt from cobalt ore. It is used 
in the manufacture of german silver or argenant, in which 
it is alloyed with copper and zinc. 
Fig. 1.—Millerite, Sulphuret of Nickel, Capillary 
Pyrites. 
Is found in capillary crystals and small hexagonal 
prisms arranged in bundles, like Fig. 1, brass-yellow to 
steel-grey, sometimes playing in a variety of colours ; 
lustre metallic, opaque, hardness 3*0—3*5, specific gravity 
/ 
5*27—5*65. It is simple sulphuret of nickel, Ni, generally, 
however, containing copper and iron; on the charcoal it 
gives sulphurous vapours, and deposits metallic copper on 
being heated in the inner flame; it is found in hornstone 
at Johanngeorgenstadt in Saxony, and at Joachimsthal in 
Bohemia, also at Duttweiller near Saarbruck, in Cornwall, 
and at Ebbw Vale near Merthyr-Tydvale, but always in 
small quantity. 
Fig, 2.—Copper Nickel, Red Arseniet of Nickel, 
Arsenical Nickel. 
Is said to crystallise in hexagonal prisms; is found, 
however, generally in a crystalline state, compact, globular, 
