57 
unites in itself the peculiarities of both; they occur in the 
iron micaceous schist of Brazil. The chemical constituents 
are peroxide of iron Fe = 69*35 of iron, 3066 of oxygen. 
There are, however, hematites which contain oxide of 
titanium, rhombohedral titanic iron to which belong, for 
example, most of the hematites of St. Gothard and the 
ilmenite of Miask. Many of these contain some protoxide 
of iron, and are then attracted by the magnet. 
The crystallised varieties are called in a general way 
specular iron , the foliated iron-glance , and if they form large 
masses of rock, as in Brazil, micaceous iron ore, and itaberite, 
the scaly varieties are called scaly red iron or red iron 
froth. When dense and compact, they are called red iron 
ore, and when fibrous, like Fig. 21, hematite ox fibrous red 
iron, when earthy, red ochre. Those containing clay are 
named reddle or red clay iron , etc. Before the blow-pipe 
they all become black and magnetic in the inner flame, in 
which the argillaceous varieties are melted to a slag; the 
others are infusible. They are only with difficulty, and 
after a long time, soluble in acids. 
Specular-iron and fibrous red iron belong to the best 
iron ores, and are smelted for iron wherever they occur in 
large quantity, as, for instance, in Styria and Carinthia, in 
Silesia, Bohemia, and Saxony; also at the Harz. The 
fibrous hematite is used also as a polish for metals, for 
making marks on stone, and, when reduced to a fine 
powder, also as a colouring material; reddle is employed in 
the manufacture of red pencils, and as a common pigment. 
PLATE XVIII. Figs. 22 and 23, and PLATE XIX. Figs. 1—6. 
Beown Hematite, Limnite. 
Is found only exceptionally in crystals and in right 
rhombic prisms, which are usually bevelled, like Fig. 22. 
This variety is called gothite, or needle-iron ore, and if it is 
in transparent laminae, rubin-glimmer; the scaly, fibrous 
variety has been called lepidokrokite , or scaly-brown iron 
ore. The fibrous, radiatingly foliated and concentric- 
fibrous, nodular, clustered, and stalactitic forms, are more 
frequent; they are of yellowish-brown or dark-brown 
colour, externally of vitreous lustre, internally silky, like 
Fig. 23 in Plate XVIII., and Fig. 1 in Plate XIX., which 
is called fibrous-brown iron ore. These are usually asso¬ 
ciated with compact or jasper-like brown iron ore, as in Fig. 
23. The crystallised varieties only, are translucent to 
semi-transparent. All have a rusty or brownish-yellow 
streak, and are brittle. The fracture is uneven or fibrous 
to splintered, the hardness = 5*0—5*5, the specific gra¬ 
vity = 3*8—4*2. They are not attracted by the mag¬ 
net. When heated in the retort they give off water, and 
leave peroxide of iron ; before the blowpipe, in the inner 
flame,, they give a black drop, which follows the magnet. 
In the borax pearl they yield, with frothing up, an olive- 
green pearl, the same as the other iron ores. In acids they 
dissolve with difficulty. The elements of the crystallised 
varieties are the hydrous peroxide of iron = Fe H; the 
fibrous varieties contain three equivalents of water to two 
of peroxide of iron. ' As the amount of water, therefore, 
varies from 10*311 to 14*71, they in general yield so much 
less iron than the red iron ores, but they belong to the best 
kind of ores, and therefore, whenever they occur in large 
amount, they are smelted for iron, as, for instance, at the 
Harz, in Nassau, Carinthia, Styria, Bohemia, Hungary, in 
the Schwarzwald, etc. 
The argillaceous brown iron ores occur principally in 
four different varieties. 
1. Kidney-shaped clay-ironstone, in roundish hollow 
masses, either compact or earthy, of a brown to an ochre- 
yellow colour, like Fig. 2, and pale yellow streak. 
2. Yellow ochre, soft, triturable, of a brownish-yellow 
colour, seen at the outside of Fig. 2. 
3. As pea-iron ore, or nodular clay-ironstone, in round¬ 
ish or obtuse-angled granules of compact or concentrically 
scaly structure, sometimes loosely embedded in yellow 
clay-iron, sometimes aggregated as a conglomerate in a 
chalky clay, as in Fig. 3, principally in fissures and clefts 
or cavities in white Jura-chalk; the bones and teeth of 
animals of the tertiary and diluvial periods are not unfre- 
quently found imbedded in it, and these may be separated 
from the pure pea-iron ore by washing, as, for instance, in 
the Swabian Alps, in the highlands of Baden, etc. There 
is also another variety found in the Elsass, mingled with 
the petrifactions of the black and brown Jura. 
4. The granular, lenticular, oolitic clay-iron ore con¬ 
sists of small grains and nodules of a reddish-brown colour, 
which sometimes occurs by itself, as in Fig. 4, Plate XIX., 
and then not unfrequently with small mussels, snails, 
etc., as, for example, at Aalen and Wasseralfingen in 
Wurtemberg, where these ores are imbedded in layers of 
from 6—12 feet deep in the lower browm Jura forma¬ 
tion ; or they are grey to blackish-brown, imbedded in 
clay or sand marl, and form the so-called iron roe-stone, 
which, in the upper brown Jura of Swabia and Switzer¬ 
land, forms considerable layers, and is not unfrequently 
smelted. 
In general, brown argillaceous ironstones yield only 
from 24—32 per cent, of iron; as they usually occur, 
however, in considerable quantity, and are easily obtained, 
and generally yield a very good sort of iron, they are fre¬ 
quently smelted, the more especially as they require only 
a very slight flux. 
Fig. 5.— Spathose Ikon, Carbonate of Iron, Siderite, 
Spelerosiderite. 
Crystallizes in rhombohedrons the same as calcite, 
with which it is isomorphous; the angles according to 
Briethaupt are 107° 41". The cleavage is parallel to 
the primary planes. Truncations of the vertical edges, 
hexagonal tables, and pyramids also occur, as well as 
foliated, compact masses and radiated globular forms; the 
common rhombohedron, like Fig. 5, is most frequent. The 
original colour is yellowish-white, with a remarkable 
vitreous to adamantine lustre, which is also seen on the 
planes of fracture. The crystals are for the most part 
translucent. By decomposition the mineral becomes 
brown or black, and the lustre and transparency are 
lost. The fracture is splintery, the structure foliated, 
the friability remarkable, the hardness — 3*5—4*5, the 
