MINERALOGY. 
215 - 
Sixteenth Genus. Arsenic . 
First species. Native arsenic. 
When fresh broken it is of a light whitish 
lead-grey colour, but it speedily tarnishes ; 
it occurs massive, disseminated, reniform, and 
in plates, with, various impressions. It is 
found in thin, curved, lamellar, distinct con- 
cretions ; in the streak it becomes sinning 
and metallic, semihard in a high degree, 
very easily frangible, and between sectile 
and malleable. It occurs only in primitive 
mountains, and in veins of a newer forma- 
tion. and is found in various parts of Ger- 
many, in France, and in Chili. 
Second species. Arsenic pyrites. 
Common arsenic pyrites is, when fresh, of 
a silver-white colour, but soon acquires a 
yellowish tarnish; it occurs massive, dis- 
seminated, and also in chrystals of various 
figures. Internally, it is shining, with a me- 
tallic lustre ; and is found usually unsepa- 
rated, ' . hard, brittle, not easily frangible, 
and heavy. It occurs only in primitive 
mountains and in beds, and is produced in 
Norway, Germany, and Siberia. From this 
ore the white oxide of arsenic is principally 
obtained, “ 
Third species. Orpiment. 
Red orpiment is of an aurora-colour, of 
different degrees of intensity : it occurs mas- 
sive, disseminated in membranes, and also 
chrystallized in oblique four-sided and six- 
sided prisms. It is translucent, but the 
chrystals are transparent, is very soft, yields 
? lemon or orange-coloured streak, and is 
easily frangible It is found both in primi- 
tive and floetz mountains, and is produced 
in Germany, France, Italy, and the West 
Indies. It is used as a pigment. 
Yellow orpiment is of a perfect lemon-yel- 
low colour, occurs massive, and in very "mi- 
nute chrystals, is found in large, coarse, and 
small angular granulated distinct concretions, 
I is translucent, very soft, sectile, and common 
flexible. It occurs principally in lloetz 
mountains, in several parts of Germany and 
the East. 
Fourth species. Arsenic bloom. 
The colour is a reddish-white and snow- 
white ; it occurs as a coating, in small balls, 
&c. and in very delicate capillary shining 
chrystals, is translucent on the edges, very 
soft, easily frangible, and soils. It is pro- 
duced in rents of a granite rock, and hitherto 
has only been discovered in Swabia. 
Seventeenth Genus. Sclieele .* 
First species. Tungsten. 
The colour is usually yellowish and grey- 
ish-white, which pass into several other neigh- 
bouring shades ; it occurs massive, dissemi- 
nated, and frequently chrystallized. Inter- 
nally it is shining, with a vitreous lustre ; is 
more or less translucent, soft, not very brit- 
tle, and uncommonly heavy. It is found in 
primitive mountains, and belongs to the 
oldest metalliferous formations, and is pro- 
duced in Cornwall, Sweden, Saxony, and 
Bohemia. 
Second species. Wolfram 
Is of an intermediate colour between dark 
greyish-black, and brownish-black; it occurs 
* So called in honour of the illustrious 
Sclieele. 
massive, and also chrystallized in broad six- 
sided prisms, and rectangular four-sided 
tables; and is found in fortification-wise 
curved lamellar distinct concretions. It is 
opaque, yields a reddish-brown streak, is soft, 
brittle, and uncommonly heavy. It is pro- 
duced in the primitive mountains, almost al- 
ways accompanied with tin, in Cornwall, and 
some other countries. 
Eighteenth Genus. Menacliine. 
First species. Menachanite 
Is of a greyish-black colour, inclining to 
iron-black, occurs only in small fiattish an- 
gular grains. Internally is glistening, with an 
adamantine lustre, is perfectly opaque, soft, 
brittle, retains its colour in the streak, is ea- 
sily frangible, and moderately heavy. It is 
attractable by the magnet, and is found in 
Cornwall, accompanied by fine quartz-sand, 
in the isle of Providence in America, and at 
Botany Bay. 
Second species. Oclrahedrite. 
Its colour passes from indigo-blue to many 
other shades; it occurs only chrystallized, 
and that in very acute octahedrons. It is 
chiefly translucent, and semitransparent, 
semihard, brittle, and borders on heavy. It 
is found in Dauphiny, and appears from ac- 
curate experiments to be an oxide of mena- 
chine mixed with silica. 
Third species. Rutile 
Is of a dark blood red colour, of various 
degrees of intensity; it occurs always chrys- 
tallized in four-sided and six-sided prisms, 
and also in compressed acicular and capillary 
chrystals. Externally it is shining, internally 
splendent, translucent in a slight degree, 
hardish, easily frangible, and not very heavy. 
It is found imbedded in drusy cavities of gra- 
nite, &c. in different parts of Germany, 
France, Spain, Siberia, and South Carolina. 
Fourth species. Nigrine 
Is of a dark brownish-black colour, passing 
to velvet-black ; it occurs in larger and 
smaller angular grains, and in rolled pieces. 
Externally moderately glittering, internally 
the same, with an . adamantine lustre, is 
opaque, semihard, brittle, and yields a yel- 
lowish-brown streak. It is found in alluvial 
hills in several parts of Germany, and also in 
Ceylon. 
Fifth species. Iserine 
Is of an iron-black colour, somewhat in- 
clining to brownish-black; it occurs usually 
in small obtuse angular grains, and in rolled 
pieces, internally glistening, with a semi- 
metallic lustre, is completely opaque, hard, 
nrittle, and retains its colour in the streak.. 
Hitherto it has been found only in the stream 
called Iser in Germany, from which it re- 
ceives its appellation. It bears a great re- 
semblance to iron-sand. 
Nineteenth Genus. Uran. 
First species. Fitch ore 
Is usually of a velvet-black colour; it oc- 
curs almost always massive and disseminated. 
Internally is shining, soft, brittle, uncom- 
monly heavy, and completely infusible with- 
out addition. It is found in veins of primi- 
tive mountains along with lean and siive;- 
ores, and is produced in Saxony and Norway. 
- Second species. Uran mica. 
The principal colour is a grass-green, pass- 
iulo various allied shades; it occurs some- 
times in membranes, but commonly chrystal- 
lized in rectangular four-sided tables. The 
fracture is foliated, the fragments and distinct 
concretions are too minute to be determined. 
It is more or less translucent, soft, sectile, 
easily frangible, and is found in iron-stone 
veins in Cornwall, Saxony, and France. 
Third species. Uran Ochre. 
Friable uran ochre is usually of a straw-yel- 
low colour : it generally occurs as a coating or 
efflorescence on pitch ore ; is friable, and 
composed of dull dusty particles, which feel 
meagre, and are not particularly heavy. 
Indurated uran ore is of the same colour as 
tire preceding : occurs massive and dissemi- 
nated, is generally dull, internally opaque, 
soft, brittle, and soils a little, and is found 
along with the other ores of uran. 
Twentieth Genus. Sylvan. 
First, species. Native Sylvan. 
Is of an intermediate colour between white 
and silver-white : occurs massive and disse- 
minated, and also chrystallized in four and 
six-sided prisms, in small three-sided pyra- 
mids, in cubes, and in short acicular chrys- 
tals. It is soft, not very brittle, easily frangi- 
ble, and heavy ; and before the blowpipe 
melts as easily as lead, burning with a light 
green colour, and emitting a sharp, disagree- 
able odour. Hitherto it has only been found 
at Face-bay, in Transylvania. 
Second species. Graphic Ore. 
Its colour is a light steel-grey: it occurs 
massive and chrystallized ; externally is splen- 
dent, internally glistening. When massive, 
it shews a tendency to tine granular distinct 
concretions: it is soft, brittle, sectile, and 
heavy, and is worked as an ore of gold in 
Transylvania, where alone it has yet been 
found. 
Third species. Yellow Sylvan Ore 
Is of a silver-white colour, inclining to 
brass-yellow: it occurs disseminated and 
chrystallized in very small and rather broad 
four-sided prisms ; is soft, rather sectile, and 
uncommonly heavy. It is found along with 
the other species of the genus, and contains a 
considerable portion both of goid and silver. 
Fourth species. Black Sylvan Ore 
Is of an intermediate colour between iron- 
black and blackish lead-grey : it occurs mas- 
sive, and in small, thin, and longish six-sided 
tables, which are usually imbedded. Ex- 
ternally it is splendent; internally shining, 
soils a little, is very soft, sectile, splits easily, 
and in thin leaves is common flexible, it 
melts easily before the blowpipe ; occurs in 
veins along with other minerals, but is only- 
found in Transylvania, where it is worked for 
the gold and silver it contains. . 
• Twenty-first Genus. Chrome. 
First species. Acicular, or Needle Ore. 
• Its colour is dark steel-grey: occurs in 
imbedded acicular chrystals; internally shines 
with a metallic lustre, is soft, not very brit- 
tle, heavy, and is always accompanied with 
chrome ochre, and sometimes with native 
gold. It is found in Siberia,. 
