MIN
MOL
( 105 )
MINERALIZER Is any fubftance found innatural combination with a metal. Thus leadis faid to be mineralized, by fulphur, when com-bined with it in the native fulphuret or galena.
MINIUM. See Lead , (Oxyds of).
MISPICKEL. See Arsenic, (Ores of).
MOONSTONE or ADULARIA. See Eel-spar.
MORDANT. See Dying, (Art of).
MORTAR . See Cements calcareous.
MORTAR (Chemical inftrument ). See theAppendix .
MOTHER OF PEARL. See Shell.
MOTHER-WATER is the uncryftallizablerefidue of a compound faline folution. Forfurther particulars fee the article Crystalli-zation.
MOLYBDENA. Molybdan , Germ. Molyb-dene , Fr.
Molybdena is a metal of a greyifh white co-lour, in the form of brittle infufible grains. Itis convertible to a yellowilh white oxyd by ex-pofure to the air at a red heat, or by the actionof nitric acid.
§ i. Ores of Molybdena.
Sp. i. Molybdena, or Sulphuret of Molyb-dena. fVaJferbleyy Wern. Molybdene fulfure,Broch.
Its colour is nearly that of frefh cut metalliclead. It occurs maflive, difleminated, and rarelycryftallized. Its primitive figure is a ftraitprifm with rhomboidal bafes, the alternate an-gles of which meafure 60° and 120 0 . It alfooccurs in Ihort regular hexahedral prifms, thebafes of which are fometimes terminated byIhort hexahedral pyramids: fometimes alfo theintervening prifm is wanting, the pyramids atthe fame time being deeply truncated. Thecryftals are fmall or middle-fized, and are al-ways implanted. Internally it is more or lefsfhining with a metallic luftre ; its fracture iscurved and fometimes radiating lamellar. Itsfragments are indeterminate and blunt edged,or in irregular laminse. It occurs in granular■diftinfit concretions. It is opake, ftains thefingers, leaves Ihining traces when drawn overP. a per; is very foft and eafily divifible in thedirection of its laminap; is fertile, eafily frang-ible, flexible but not elaftic, and is unctuousto the touch. Sp. gr. 4.56 to 4.73.
t 1 - IS “afufible before the blowpipe but exhalesa fulphureous odour: at a very high heat itmelts, gives out white fumes and burns with ablue flame; by a long continuance of the heat
VOL. II.
it is converted into a mafs of yellow and delicateneedleform cryftals.
Its conftituent parts are probably fulphur andmetallic molybdena, but the proportions havenot yet been afcertained with much accuracy.
According to Pelletier it confifts ofMolybdic acid - - 45Sulphur - - - - 55
100
Some of the early experiments of Klaproth induced him to ftate its ingredients atMolybdena - - - 60Sulphur - - - - 40
100
Laftly, Lampadius has analyzed this mineral,and finds it to be compofed of
Molybdena - -Sulphur - - -Iron - - - -
- 76
- 23
100
Molybdena occurs difleminated or in veins, inprimitive mountains accompanied by tinftone,wolfram, quartz, mica, and rarely with nativearfenic, heavy fpar, fluor fpar, and topaz. It isfound at Hitterdahl and Arendahl in Norway ;Baftnaes in Sweden; Altenberg and Zinwald in Saxony; Mont Blanc in Switzerland .
Sp. 2. Molybdat of Lead . Yellow Lead-fpar. Gelbes Bleyerz, Wern. Plomb jaune yBroch. Plomb Molybdat Hauy.
The ufual colour of this mineral is wax yel-low, which pafles either to lemon or orange-yellow or fometimes to a dirty honey-yellow.It occurs for the molt part cryftallized, veryrarely maflive. Its primitive figure is a re£tan-gular octohedron with ifofceles triangular faces :the incidence of the faces of one pyramid onthe correfponding ones of the other is 76° 40’.The other varieties of form that it exhibits are,
1. The primitive oftohedron with either allthe folid angles or only the two vertical onesreplaced by quadrilateral prifms.
2. The fame as the preceding, with the la-teral edges of the pyramids replaced by narrowtriangular faces, and therefore the four fecond-ary faces round the common bafe of the pyra-mids are not quadrilateral but hexagonal planes.
3. A rectangular parallelepiped fometimesfo thin as to be tabular, fometimes approachingto the cube.
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