66 
tion, and even these compounds are very sparingly distri¬ 
buted. The metal has no application in the arts or 
sciences, and was first discovered in pitch-blende by 
Klaproth in 1789. It is iron-grey in colour, very hard, 
not magnetic, difficult of fusion, of 9*0 specific gravity, and 
crystallises in regular octahedrons, 
Fig. 7.—Pitch-blende. 
May crystallise in regular octahedrons, hut is found for 
the most part only in botryoidal, globular, and com¬ 
pact forms, in blackish brown, slightly lustrous masses, of 
greasy to metallic lustre, of conchoidal to uneven fracture, 
very rarely foliated, so that the 1 ami me appear to corre¬ 
spond to the planes of fracture. The streak is iron-black, 
the hardness = 5*5, and the specific gravity = 6*46. The 
composition is essentially protoxide of uranium U, in which 
small proportions of protoxide of iron, oxide of manganese, 
silica, and sometimes also oxide of lead occurs. Melts 
before the blow-pipe with borax to a grey glass, and with 
salt of phosphorus a yellowish green bead. 
The most important ore of uranium, which is principally 
used as a yellow and yellowish-green pigment for painting 
on glass and porcelain. It occurs not unfrequently in 
Johann-Georgenstadt, Schneeberg, and Joachimsthal in the 
Erzgebirge, and also in Cornwall, where it has been sold 
for £30 a ton. 
ZlPPEITE, URANOCHRE. 
Is an earthy lustreless mineral, of a sulphur to orange 
yellow colour, which, with borax, gives a yellow glass in 
the outer flame, and a green in the inner. 
Uranbloom is a carbonate of urania, which occurs with 
the foregoing in crystalline flakes of pearly lustre and 
bright orange yellow colour, especially at Johann-Georgen¬ 
stadt. In Fig. 8 both minerals are figured, the former 
at the left and the latter at the right. 
Fig. 12.—Uranite. 
Crystallises in quadratic prisms and tables, as in Figs. 
11 and 12, of remarkable pearly lustre, distinct foliated 
structure, 2*0—2'5 hardness, and 3T—3 ’3 specific gravity. 
We have (1.) Uranite , consisting of phosphate of uranium 
and phosphate of lime, which occurs in greenish-yellow 
square tables, especially at Autun in France, Fig. 9 ; (2.) 
Chalcolite , Fig. 10, consisting of phosphate of uranium 
and oxide of copper, of emerald-green colour. Both con¬ 
tain 24 equivalents, or 15 per cent, of water. The latter 
is found chiefly at Johann-Georgenstadt and in Cornwall. 
In the retort, and before the blow-pipe, both give the reac¬ 
tions of water and of oxide of uranium, the latter variety 
also gives those of oxide of copper. The specimen 
figured is from Redruth, Cornwall. 
Fig. 13—21.— Titanium Ores. 
Titanium is a metal occurring only very sparingly in 
nature, which was first discovered in 1791. It is brittle, diffi¬ 
cult of fusion, hard, almost silver-white, and is sometimes 
found in combination with nitrogen in burned-out furnaces, 
in which titanic iron ores have been smelted, crystallised in 
copper-coloured, cubes. Until the present time it has been 
applied to no particular purpose. The oxygen compounds 
in which it occurs in nature are the more remarkable, 
since the oxide of titanium, for instance, is found in three 
different forms, and is trimorphous ; on the other hand, it 
takes, in many iron ores, the place of the oxide of iron, 
and thus gives both octahedral and rhomhohedral titanic 
iron. 
Fig. 13—15.— Anatase. 
Crystallises as an acute quadratic octahedron, Fig. 13 ; 
but also occurs in combination with the square prism, Fig. 
14, truncated at the vertex, Fig. 15, and exceptionally in 
square tables of dark brown, reddish and blackish colours, 
of adamantine to vitreous lustre, translucent, friable, of light 
streak, 5*5—6*0 hardness, and 3*82 specific gravity. It is 
oxide of titanium, Ti, consisting of 60*29 of titanium and 
39*71 of oxygen; infusible by itself. When melted with 
soda it gives a greyish glass, and with borax and salt of 
phosphorus colourless pearls. 
It is found at St. Gothard, in Dauphinee, at the 
Fichtelgebirge, in Spain and Brazil, and in Cornwall and 
Devonshire. 
Figs. 16 and 17.— Rutile. 
Crystallises in quadratic prisms, which are generally 
striated longitudinally, and exhibit a conchoidal to an uneven 
fracture, sometimes also, as in Fig. 16, they are truncated at 
the lateral edges and bevelled at the angles ; still more 
frequently they occur in twins and triplets, as in Fig. 17, 
or in thin needles, blood-red to hyacinth-red, translucent, of 
metallic lustre, with brown-red streak, 6*0—6*5 hardness 
and 4*24 specific gravity. It occurs pretty frequently in 
the Alps, Switzerland, and the Tyrol, in Carinthia and 
Styria, in France and Norway; it is also found occasionally 
in Glamorganshire, in large prisms and fibrous masses at 
Crianlarich in Perthshire, and at a few other localities in 
Scotland. 
Fig. 18.— Brookite. 
Crystallises in right rhombic prisms and tables, mostly 
truncated at the obtuse lateral edges and at the basal 
edges, as in Fig. 18, and like the two foregoing ores con¬ 
sists of oxide of titanium. It forms the third rhombic form 
of the oxide of titanium. It is brownish-red, of adaman¬ 
tine to metallic lustre, of 5*5—6*0 hardness, and 4*13— 
4*16 specific gravity. Otherwise its relations are the same 
as the foregoing. It is found at Snowdon in North Wales, 
at d’Oisans in Dauphinee, at St. Gothard, and Rutherford 
in North Carolina. 
Figs. 19 and 20.— Sphene. 
Crystallises in oblique rhombic prisms, which are 
