58 
specific gravity 3*6—3*9. The pare spathose iron con¬ 
sists of protocarbonate of iron Fe C, composed of 61*37 
protoxide of iron, and 38*63 of carbonic acid; it frequently 
also contains protocarbonate of manganese, and the car¬ 
bonates of lime and magnesia. The globular and compact 
varieties of fibrous or earthy fracture are called Sphcerosi- 
derite , and the latter frequently form, in the clay schists 
of the coal formations, considerable beds, which are used 
for iron, and not unfrequently enclose fishes, sauria, and 
the remains of plants, as for example in the Saarbruck, at 
Liittich, etc. The black-band is a similar iron-ore of a 
steel-grey or coal-black colour, of the appearance of schistic 
anthracite, containing about 63 per cent of protocarbonate 
of iron, which has been found in the coal formations 
of Staffordshire, South Wales, and Lanarkshire, and also 
at Saarbruck. It also yields a good variety of iron, which 
is mostly appropriated to the manufacture of steel. 
Before the blow-pipe, in the inner flame, the spathose 
iron ores give the peroxide and protoxide of iron, which is 
attracted by the magnet. They are soluble in nitric acid 
with effervescence, and some of the clay which is present 
is also separated. 
The finest crystals of spathose iron are obtained from 
the mines of Neudorf in the Harz, from Altenberg and 
Ehrenfriedersdorf in Saxony, and Lobenstein in Yogtland; 
the compact variety occurs at the Stahlberg in Nassau, at 
Schmalkalden, and in Styria. These pure spathose iron 
ores yield principally the white specular iron, so highly 
valued for the manufacture of steel. The clay sphgerosi- 
derites are found almost wherever the coal formations 
exist, and the mammillary sphserosiclerite for the most part 
in the dolerite of Steinheim at Hanau. 
Mesitine-spar is the name which has been given to a 
combination of equal proportions of protocarbonate of 
iron and carbonate of magnesia, which occurs in rhombo- 
hedral lenticular forms of silky lustre at Traversella and 
at Duttweiler. Oligon-spar is a compound of like equiva¬ 
lents of oxide of manganese and of the protoxide of iron; 
it is also rhombohedral, and occurs at Ehrenfriedersdorf in 
Saxony. 
Figs. 6 and 7. —Phosphate of Iron. 
* 
The combinations of the oxide of iron with phosphoric 
acid are practically of very little importance, the bog-iron 
ore only being smelted when it occurs in large quantities, 
and principally for cast-iron. 
Bog-iron ore (Fig. 6) is a hydrous oxide of iron 
generally containing clay mixed with a phosphate of iron, 
sometimes found in roundish lenticular forms, sometimes 
in shapeless masses of a yellowish-brown colour, princi¬ 
pally in such situations as where standing water is acting 
upon ferruginous rocks; and different marshy plants are 
occasionally found in it, similar to those found in peat¬ 
mosses. There are several varieties, distinguished accord¬ 
ing to the peculiarities of their occurrence, but all of them 
give a brownish-yellow r streak, and contain, in addition to 
phosphate of iron, water, alumina, silica, and generally a 
little oxide of manganese. The sandy iron ores are partly 
in the form of plates, partly cylindrical, and frequently 
form long cylindrical tubes of 1—8 inches in diameter; 
besides the elements already mentioned, they generally 
contain some quartz-sand. They occur pretty frequently 
in Northern Germany. Bog-iron ore is found in the 
Pfalz, in Pomerania, Holstein, Sweden, and Russia, some¬ 
times in considerable quantity, so that it is smelted. 
Vivianite or blue iron earth , Plate XIX. Fig. 7, crystal¬ 
lises in oblique rectangular prisms, and occurs especially 
with truncations of the edges, like gypsum, also radiated, 
foliated, and earthy, of an indigo-blue colour, vitreous lustre, 
translucent, of distinct foliated structure, of 1*5—2*0 hard¬ 
ness, and 2*6—2*7 specific gravity. It is sesqui-phos- 
phate of iron, with 6 equivalents of water, and melts in 
the inner flame to a grey lustrous granule of phosphate of 
iron. Fine crystals are found at Bodenmais in Bavaria, 
in Cornwall, and in Auvergne. The earthy vivianite is 
formed in marshes and peat-bogs, and is deposited in the 
shape of a fine powder in wood, peat, etc. It occurs in 
Holstein, Swabia, and Silesia, but generally only in small 
quantities. Dufrenite or green iron ore is a dark green 
and hydrous phosphate of iron, of radiated fibrous struc¬ 
ture, of 3*5 hardness, and 3*2—3*4 specific gravity, which 
is found in botryoidal, nodular, fibrous, and radiated masses, 
at Johann Georgenstadt in Saxony, Bieber in Hesse, and 
Schindeloh in Bavaria. 
Figs. 8 and 9.— Arseniate of Iron. 
The compounds of the oxide of iron with arsenious 
acid have only a scientific interest, and they are also of 
but rare occurrence. 
The scorodite crystallises in rhombic octahedrons, which, 
as in Fig. 8, are truncated at the angles, and generally 
bevelled at the basal angles, of vitreous lustre, bluish green 
colour, of 3*16 specific gravity, and 3*5— 4*0 hardness. 
It is an arseniate of iron, with 4 equivalents of water, and 
is found especially fine at Schwarzenberg, and Schneeberg 
.in Saxony. 
Cube iron ore crystallises in cubes of a light green to 
an olive green colour (Fig. 9), of vitreous lustre, translu¬ 
cent, of 2*5 hardness, and 2*9—3 specific gravity. It is 
one-third arseniate of the protoxide, with two-thirds of 
arseniate of the peroxide of iron and 18 equivalents of 
water, and occurs principally at Schwarzenberg, and at 
Freudenstadt in the Schwarzwald. 
Before the blow-pipe both ores give off in the reducing 
flame watery vapours and an arsenious smoke, and at last 
leave a grain which is attracted by the magnet. 
The pitticite , or colophony iron, is an amorphous 
arsenical hydrous oxide of iron, with the appearance and 
resinous lustre of brown colophony, and marked conchoidal 
fracture, which is found particularly fine at Graul, near 
Schwarzenberg, and formerly occurred also at Wheal Spar¬ 
row in Cornwall. 
Fig. 10.—Sulphate of Iron. 
Crystallises in oblique rhombic prisms, of bluish-green 
colour, vitreous lustre, translucent, of 2*0 hardness, and 
1*8—2*0 specific gravity ,* it is found, however, for the 
most part in the walls of old mines in stalactitic or 
botryoidal forms, of crystalline structure when of more 
recent formation, or in fine needles and efflorescences, 
and consists of decomposed iron pyrites. It is sulphate 
