68 
sisting of one equivalent of molybdenum and three equiva¬ 
lents of oxygen. 
Figs. 3 and 4. —Chrome Ores. 
Chromium was discovered by Buckland in 1797, and 
forms a greyish passing into a tin-white, friable, non-mag- 
netic metal, difficult of fusion, and of 5'9 specific gravity. 
It only occurs in nature in combination with oxygen ; 
most frequently the combinations are with the protoxide 
of iron and oxide of lead. 
Chromic iron-stone , octahedral chrome ore, crystallises 
in regular octahedrons, like Fig. 4, or in compact granular 
masses of an iron-black colour, as in Fig. 3, of slight 
metallic lustre, uneven fracture, 5‘5 hardness and 4 - 4—4*5 
specific gravity, opaque and friable ; it is chromate of iron 
Fe €r, in which, however, part of the protoxide of iron 
is sometimes replaced by magnesia or protoxide of man¬ 
ganese and the oxide of chrome, by alumina or oxide of 
iron. It is not magnetic, but becomes so in the reducing 
flame. It is soluble with difficulty in borax, and gives an 
emerald-green pearl. It is found at Kraubat in Styria, 
Roraas in Norway, Baltimore in North America, at Nantes 
in France, in Sweden and in Scotland, sometimes in con¬ 
siderable masses, and is principally used for the prepara¬ 
tion of chromic acid and its compounds, as well as the 
oxide of chrome, which is generally applied to glass and 
porcelain painting. 
Chrome Ochre is an apple-green earthy encrustation, 
which sometimes occurs with chromite, as in Fig. 3, and 
which also yields an emerald-green glass with borax. It 
is for the most part an oxide of chrome 0, rendered im¬ 
pure by silica and alumina. 
Fig. 5—10.—Antimony Ores. 
Antimony is a metal w T hich not unfrequently occurs in 
nature, native as well as in combination with sulphur or 
oxygen, sometimes also with other electro-positive metals, 
gold and silver for instance, it takes the electro-negative 
part of the sulphur. All its compounds before the blow¬ 
pipe give a white inodorous vapour, which stains the 
charcoal white, and is easily blown off; the oxides give a 
colourless pearl with borax. 
Fig. 5.—-Native Antimony, Stibium. 
♦ 
Crystallises in rhombohedrons, which are sometimes 
truncated at the basal edges, like Fig. 5 ; more frequently 
it is found in crystalline foliated masses, which may be split 
in the direction of the rhombohedron. It is tin-white, 
friable, of strong metallic lustre, opaque, of 3*0—3*5 hard¬ 
ness and 6*6—6’7 specific gravity. It melts very readily 
on the charcoal, and evaporates even while cooling; and 
the test is also covered with white oxide of antimony. 
Sometimes it contains traces of arsenic, silver, and iron; 
the first may be recognised by the odour given off in heat¬ 
ing, and the two others remain behind on the charcoal. 
It is readily soluble in nitric acid, and the solution gives an 
orange-yellow precipitate with sulphuretted hydrogen. It 
is found only sparingly at Andreasberg in the Harz, Przi- 
bram in Bohemia, and Allemont in France. The metal 
antimony is principally used in letter-founding and stereo¬ 
typing, and in several alloys ; it is, moreover, used for all 
kinds of chemical apparatus and various colours, and the 
metal is for the most part obtained from grey antimony 
glance, or antimonite. In former times it played a con¬ 
siderable part in alchemy, the compounds with sulphur 
having been known much earlier, although the metal was 
first discovered in the fifteenth century. The Chinese 
have also employed it from a very early period in com¬ 
bination with copper, tin, and zinc, for the manufacture of 
the alloy known as tutenague or white copper. 
The application of antimony to these alloys depends 
principally on the peculiarity it possesses of making other 
metals hard, and at the same time easily melted. 
Fig. 6—8.—Antimonite, Stibine, Grey Antimony 
Glance, etc. 
The primary form is a rhombic octahedron, which, 
however, is for the most part in combination with trunca¬ 
tion of two basal edges and basal angles, as in Figs. 6 and 
7 ; yet more frequently it is found radiated in bundles, 
like Fig. 8, or foliated, granular, etc. The crystals are 
frequently curved and striated horizontally, like Fig. 7 ; 
iron to lead-grey, of metallic lustre, iron-grey streak, but 
little friable, opaque, of 2'0 hardness and 4%o—4*7 specific 
gravity. Generally it leaves a mark on white paper. The 
n f 
composition is sesqui-sulphuret of antimony Sb, consisting 
of 72‘8 antimony and 27’2 of sulphur; occasionally it 
contains traces of arsenic, which may be recognised before 
the blow-pipe by the peculiar odour given off. It melts 
readily, and burns with a bluish flame, gives off white 
fumes, and is entirely consumed. 
It is found principally at Wolfsberg in the Harz, 
Chemnitz and Schemnitz in Hungary, Przibram in Bo¬ 
hemia, Braunsdorf in Saxony, and in many other localities. 
It is the most important of the antimony ores, from which 
most of the other preparations of antimony are obtained. 
It is also used in medicine. 
Fig. 9.— Red Antimony Ore, Kermesite. 
Crystallises in oblique rhombic prisms and needles; 
more frequently, however, it is found in cherry-red 
bundles, and capillary crystals of adamantine lustre, as 
Fig. 9, radiated, capillary, &c. It is very soft, TO—1 *3, 
sectile, flexible, and gives off colour, of 4*5 specific gravity, 
and cherry-red streak. The constituents are 1 equi¬ 
valent of oxide of antimony and 2 eq. of the sesqui-sul¬ 
phuret of antimony. In the retort reddish sulphuret of 
antimony is sublimed, and there remains behind oxide of 
antimony; on the charcoal it fuses readily, and volatilises 
with a sulphurous odour. 
Fig. 10.—Oxide of Antimony. 
This occurs in nature in two different forms, namely, 
