Metal*. MINER. 
times blue, fometimes fpeckled ; often in the form of 
ifars, as feen in the figure; and fometimes contain a little 
gold. Fig. 9 is a red ore of antimony : like the former, 
jc is compofed of needles; but they are fmaller, more 
compact, and reprefent fine brilliant ftriae. The red co¬ 
lour proceeds molt likely from a mixture of iron. 
Fig. io reprefents a piece of yellow arfenic, or orpiment. 
Fig. n is regulus of cobalt. Fig. 12, .an ore of wolfram, 
called by the Germans iron-tin. 
Molybdenum.—G enericcharacters: Bluilh-grey, not 
tarnifliing ; brittle, not magnetic, compofed of fcaly par¬ 
ticles cohering together; fpecific gravity, 7-5; nearly in- 
fufible, gradually becoming a white volatile oxyd when 
heated, which with borax forms a violet, and with micro- 
cofmic fait a green, glafs ; partly folublein fulphuric acid, 
and giving the folution firft a green and then a blue colour. 
Scheele found this fubftance to confilt of fulphurand a 
white powder which poffeffed acid properties, and which 
he denominated the acid of inohjbdena. Bergman was the 
firft who fufpeCted this acid to be the oxyd of a metal. 
He accordingly requefted Hielm in the year 1782 to make 
fome experiments with a view to determine this faCt. 
This experimental ill mixed the acid of this metal with 
linfeed oil into the form of pafte. This was expofed in a 
dole crucible, lined with charcoal, to a very ftrong heat. 
By this means he fucceeded in reducing the metal. In 
order to obtain it in greater purity, he firft roafted the ore 
to expel the fulphur, which reduced it to the ftateof pow¬ 
der. This powder being made very fine, he next dilfolved 
it in ammonia, filtered the folution, and then evaporated 
it to drynefs. By boiling this refiduum with nitric acid 
he obtained a white powder, which was the molybdic acid. 
This being mixed with oil, and treated as before, afforded 
the metal in fmall grains. This metal is fo very infufible, 
that it has hitherto not been obtained but in fmall granu¬ 
lated bits. On this account we know very little of its 
phylical properties. Its metallic nature, however, has 
been clearly made out, by the additional labours of Pel¬ 
letier, Heyer, and Hatchett; for whofe experiments upon 
the oxyds of this metal, and other particulars, fee the ar¬ 
ticle Chemistry, vol. iv. p. 266, 7. 
Molybdsenum, then, occurs in two forms only : firftly, 
in an acid ftate united with lead, for which fee p. 502, 3. 
fecondly, combined with fulphur. 
Molybdenum vulgare, or fulphuret of molybdenum, is 
found in France, Spain, Sweden, Saxony, Siberia, and 
Iceland, in gangues of felfpar, lithomarg, or quartz ; 
generally in mali'es confifting of fmall grains agglutinated 
together, fometimes cryftallized in fix-lided tables. Co¬ 
lour light lead-grey, with fometimes a lhade of red ; ftreak 
bluilh-grey, metallic ; powder bluilh ; Toft, opake, flam¬ 
ing the fingers, and feeling a little greafy to the touch. 
Texture lamellar, with the foliations thin, incurved, and 
flightly flexible. With warm nitric acid it effervefces, 
leaving a grey oxyd undiffolved ; before the blowpipe it 
evaporates in white fulphurous vapours. Specific gravity, 
4'738. Contains molybdsenum 60, fulphur 40. 
Uranium, Uranite,—Generic characters : Dark-grey 
inclining internally to brown, with a flight luftre; foft, 
brittle ; fpecific gravity, 6-44 ; hardly fufible before the 
blowpipe, but with borax forming a brown, and with mi- 
crocol'mic fait a grafs-green, glafs : convertible into a yel¬ 
low oxyd by the nitric acid. See Chemistry, vol. iv. 
p. 268. 
1. Uranium ochraceum, or uranitic ochre: yellowilh 
or green, of an earthy texture, entirely foluble in nitric 
acid, combined with a large portion of oxygen. Gene¬ 
rally found on the furface of U. fulphureum, or pech- 
blende, in Cornwall, &c. It flightly ftains the fingers : 
is hardly fufible before the blowpipe, but in a ftrong heat 
becomes black. Specific gravity, 3'243. Confifts of oxyd 
of uranium and oxygen. 
2. Uranium chalcolithus, or micaceous uranitic ore : 
hardilh, diaphanous, iliining internally, of a foliated tex- 
\ L O G y. Metals. 515 
ture, entirely folublein nitric acid. Found in Cornwall, 
near Eibenftock and Johngeorgenftadt in Saxony, and 
near Rheinbreidenbach in the electorate of Treves ; fome¬ 
times on the furface of other ores, lometimes in larger or 
lefs particles mixed with rocks of gneifs, garnet, or quartz, 
molt commonly cryftallized in cubes, fquare plates, eight- 
fided or fix-fided prifms. Colour emerald or grafs green, 
often inclining to lilvery-wh ite or yellowilh,with a greenifti- 
white ftreak; foluble in nitric acid without effervefcence, 
but infoluble and infufible by alkalies. Confifts of oxyd 
of uranium, carbonic acid, and the green kind a little 
oxyd of copper. Specific gravity, 3-12. It is diftinguilh- 
ed from mica by its want of elafticity ; and by its folubi- 
lity in nitric acid ; and from muriat of copper, for which 
it has been miftaken, by not communicating'a blue and 
green colour to the flame of a candle. 
3. Uranium fulphureum, fulphurated uranite, or pech- 
blende : hardilh, very ponderous, black, compaCt, Alining 
internally. It is called pechblende, or pitch-blende, from 
its refemblance to the black variety of fulphuret of zink, 
for which fee p. 506. Found at Johngeorgenftadt in 
Saxony, either forming entire thin ft rat a alternating with 
other ftratified minerals, or maflive and difperfed. Colour 
black, dark grey, or bluilh-black, with a darker ftreak and 
opake black powder; texture conchoidal, very brittle; 
imperfectly foluble in fulphuric and muriatic acids, but 
perfectly in nitric and nitro-muriatic acids, giving the 
folution a vinous yellow ; forming a grey opake flag with 
borax and foda, and a green glafs with microcofmic fait. 
Specific gravity, 6^378 to 7'$. Contains uranite 86*5, ful- 
phuret of lead 60, filex 5, oxyd of iron 2‘5. 
Titanium, Titanite.—Generic characters : Very hard, 
in miilute agglutinated grains; not fufible by any known 
heat, but when expofed hot to the open air forming a blue 
or purple oxyd; precipitating a white powder when its 
cryftals or red oxyd are fufed in four times their weight of 
potalh, and the whole diffolved in water. Dr. Clarke has 
afcertained that this metal, when pure, is not red, asftated 
in books of chemiftry ; but black, exhibiting the luftre of 
pure polilhed iron when filed. Journal of Science and the 
Arts, vol. ii. p. 115. 
1. Titanium menackanita, or menackanite : in fmall 
irregularly-lhaped grains, black, eafily pulverifed, and the 
powder attracted by the magnet. Found in the valley of 
Menackan in Cornwall, alfo in America and New Hol¬ 
land, in fmall grains refembling gunpowder, of no deter¬ 
minate Ihape, and often mixed with fine grey fand ; it 
does not detonate with nitre, but melts with two parts 
of fixed alkali into an olive-coloured mafs, from which 
nitric acid precipitates a white powder 5 and this powder 
mixed with diluted fulphuric acid fo that the mafs be not 
too liquid, and evaporated to drynefs, produces a blue 
mafs; before the blowpipe it does not decrepitate, but 
with microcofmic fait it acquires a greenifli tinge, which 
becomes brown on cooling. Specific gravity, 4'427. 
Contains oxyd of iron 46, oxyd of titanium 45, with fome 
filex and manganefe. 
2. Titanium iferina, or iferine : in fmall rounded grains, 
browmilh black, hard, brittle, of a conchoidal texture, not 
attrafted by the magnet. Found in the fand of the river 
Ifer in Bohemia ; of an iron-black colour tending to 
brown ; and is hard, heavy, and brittle. 
3. Titanium ruthila, ruthiiite, or oxyd of titanium : 
compact, reddilh-brown, opake, of a foliated texture, 
forming a violet-black glafs with microcofmic fait. It is 
generally cryftallized in four or fix tided prifms, or aci- 
cular. Specific gravity, from 4'180 to 4^246 ; when pure, 
it is composed entirely of oxyd of titanium. This mine¬ 
ral is found near Limoges in France, in Hungary, at St. 
Gothard in Swifferland, on the Carpathian .mountains, 
near Burgos in Spain, in Siberia, on the fummit of Sierra 
de Avilla, in New Granada in South America, and in 
South Carolina in North America. 
A variety called Analufe is found in Dauphiny, varying 
in 
