Metals. 
MINERALOG Y. 
Metals. 
5'liJ 
ccfs of roafting, and collefting the volatilized oxyd in 
flues connecting with the chambers in which the ore is 
roafted. This ore very much refembles the native alloy 
of cobalt and arfenic: the colour of the latter has often 
a faint ffiade of red, by which it may be diftinguifhed ; 
and its form is a modification of the cube, while that of 
the fubftance under confideration is prifntatic. It con¬ 
tains a great deal of iron, but no fulphur. 
7. Arfenicum argentiferum, argentiferous arfenical py¬ 
rites : of a filvery luftre and very fine granular texture; 
emitting arfenical vapours before the blowpipe, and, when 
fufed with lead, leaving a filver bead. Found in the 
mines of Saxony, Bohemia, Germany, and Spain, maffive, 
diffeminated, or acicular. Colour nearly that of the laft, 
but brighter and more permanent: it burns with a white 
flame, and leaves a reddifh refiduum. By folution in ni- 
tro-muriatic acid, the fdver will be precipitated. It con- 
fifts of arfenic, fulphur, iron, and from 1 to 10 or 12 per 
cent, of filver. Specific gravity, 4. 
Coealtum, Cobalt.—Bluifh-grey, with often a fliade 
of red; hardifh, very brittle; attracted by the magnet, 
and itfelf convertible into magnet; fpecific gravity, 8-15 : 
in a red heat gradually becoming a blue powder, which 
becomes deeper, and at laft a deep black-blue; in a vio¬ 
lent heat burning with a red flame; when fufed with bo¬ 
rax, producing a fine blue glafs : giving a reddifh colour 
to its folution in nitric acid, and precipitating a blue 
powder with the addition of potafh. 
1. Cobaltum nigrum, or native oxyd of cobalt: incon- 
fpicuous, of a dufky colour, emitting no arfenical vapours 
when thrown on hot coals. There are two varieties; one 
friable, of a loofe earthy confidence; the other indurated. 
Found in the mines of Great Britain, Aiiftria, Saxony, 
Hungary, Germany, Sec. This ore, which does not often 
occur, is of a black colour, and earthy appearance; but, 
if rubbed with any hard fubftance, its l'urface becomes 
brilliant: and this is a very good diftinftive mark of it. 
When pure, it is particularly valuable; as already exift- 
ing in a fit ftate for the purpofe of colouring glafs, &c. 
without the neceffity of being roafted. 
A mine of this ore was difeovered a few years ago at 
Alderley Edge in Chefhire. Alderley Edge is an emi¬ 
nence fituated about five miles weft from Macclesfield, 
from which place the road rifes by an almoft impercep¬ 
tible afeent through narrow fandy lanes : the fand chiefly 
of a reddifh-brown colour. In this red fand-ftone the 
cobalt is found. It had long been unnoticed, or em¬ 
ployed in mending the roads, until a miner, who had 
worked upon the continent, and feen the cobalt-ores of 
Saxony, firft difeovered it in the eftate of a gentleman in 
the neighbourhood. The attention of the tenants of the 
Alderley-mines was then direfted to the fubjeft, and the 
cobalt-mines were let for one thoufand pounds per ann. 
to a company near Pontefraft, in Yorkfhire. The pro¬ 
prietor of Alderley Edge is fir J. T. Stanley, bart. whofe 
grounds and feat are in its immediate vicinity. The ores 
of cobalt, fo valuable to the manufafturers of porcelain 
and paper, are very fcarce in this ifland. They have been 
found in fmall quantities in Cornwall, chiefly of the kind 
called grey cobalt-ore, which contains cobalt combined 
with iron and arfenic. The ore at Alderley is in the 
form of grains, of a bluifh-black colour. The beft f'peci- 
mens in colour and appearance refemble grains of gun¬ 
powder, diffeminated m red fand-ftone, or lying in thin 
fleams between the ftone, which has a fhiftofe or flaty 
fracture. It lies from eight to ten yards under the fur- 
face, and is got out in thin pieces, and feparated after¬ 
wards as much as polfible from the ftone ; it is then packed 
in tubs, and fent near Pontefraft, where it is manufac¬ 
tured into finalt. Amidft the confufion of mineral fub- 
ftances at this place, there are fome diftinft features of 
regularity. The cobalt-ore is ftratified, and, though near, 
is feparate from the other ores : it is chiefly, if not en¬ 
tirely, in the red fand-ftone. It lies near the furface, and 
Vol. XV. No. 1061. 
is evidently of later formation than the other part of the 
hdl; as the red fand-ftone, where it is'found, always lies 
upon, and interfefts, the white. The quality of th» finalt 
produced from it does not equal that made from foreign 
cobalt. Whether this inferiority arife from the nature 
of the ore, or fome deleft in the procefs of feparation 
may be_doubtful Cobalt is one of the moll refraftory 
metals 111 the hands of the chemical analyft It is fo in 
timately combined with iron, nickel, and arfenic, that 
its feparation, in a ftate of perfeft purity, is u procefs re¬ 
quiring great care, and attended with confiderable diffi 
culty. _ The works of the company at Pontefraft, owin°- 
to particular circumftances, and the difficulties attending 
other extenfive fpeculations, were fufpended at the cloffi 
of the year 1810. Monthly Mag. Feb. 1811. 
2. Cobaltum ochraceum, or cobalt ochre: inconfui 
cuous, earthy internally, of a paler colour, emitting arfenf 
cal vapours when thrown on hot coals. There are three 
varieties of this; brown, yellow, and green They a-e 
found in the mines of Great Britain, and various parts of 
the continent, generally deposited on other ores, thouoffi 
fometimes found botryoidal, or kidney-fhaped. Colour 
various fliades of brown, reddifh, yellowifh, green or in 
dining to blue: it very readily forms a glafs of Various 
lhades or blue. 
3. Cobaltum cobaltigo, or arfeniat of cobalt: radiated 
red, with a glaffy luftre, emitting arfenical vapours when 
thrown on hot coals. Found near the lakes of Kiilarnev 
in Ireland, and in molt places where the other ores of 
a kound; fometimes maflive, fometimes in the ftate 
of flowers: colour various fliades of red, from pale peach 
bloflom red to deep crimfon : fometimes it is found d»- 
pofited on different ftones in the form of fmall four-fided 
pnfmatic cryftals dilpofed in a ftellate or radiate manner 
which are finning, femi-tranfparent, and foft to the touch •• 
it conlifts of cobalt combined with the arfenical acid” 
The mine in the vicinity of Killarney was difeovered by 
Mr. Rafpe in the year 1794, and is faid to be the richeit 
in Europe; a ton of the ore is computed, at a moderate 
calculation, to be worth 250I. fterling; and what renders 
tins ore more precious is, that it is in great demand in 
China, where the Eaft-India Company export annually 
to the amount of 180,000k worth, which they principally 
draw from Saxony at a very heavy expenfe. 1 * 
4. Cobaltum ftercoreum, or dirty cobalt: i’nconfpicuous 
of a dirty mixed colour; when burnt and fufed with lead’ 
leaving a bead of filver. Found-in the mines of Norway’ 
Saxony, Germany, Hungary, andDauphiny; contains a 
mixture of filver, iron, fometimes nickel, arfenic, rarely 
quickfilver, in fuch indeterminate proportions as to make 
it difficult to fix its genus. 
5. Cobaltum fulphuratum, or fulphurized cobalt - of a 
tin-white colour and luftre, emitting fulphurous vapours 
when thrown on hot coals, and at length leaving a pure 
oxyd of cobalt. Found 111 Sweden and Hungary, fonie- 
times maffive, fometimes in cubical cryftals without ftria: - 
and is compofed of cobalt and fulphur with arfenic or 
iron. Front the mine at Nya Baltnais, near Riddar- 
hyttan, in Sweden. Hifinger found its conftituents 
follows: 
Cobalt 
Copper 
Iron - 
Sulphur - 
Earthy matter - - - 0-37 j 
6 . Cobaltum pyriticofum, or white cobalt ere: of a 
fteel-wliite colour and luftre, emitting fulphurous va¬ 
pours before the blowpipe, and when heated with pow¬ 
dered charcoal leaving a magnetic bead. Found in the 
mines of Hungary, Saxony, Bohemia, See. maffive, dift'e- 
minated, or cryftallized in fmall four-fided prifms or 
cubes, or double quadrangular pyramids : texture gene¬ 
rally fine-grained, rarely ftriated, or divergently fibrous; 
contains cobalt combined with fulphur and iron. 
- P 7- Cobaltum 
as 
43-20") 
14-40 j 
3*53 y 
3 s '5o 
m 100 parts. 
