ORES OF LEAD. 151 
Composition. Pb Os Cr=Chromium trioxide 31:1, lead 
oxide 68:9. Blackens and fuses, and forms a shining slag 
containing globules of lead. 
Obs. Occurs in gneiss at Beresof in Siberia, and also in 
Brazil. 'This is the chrome yellow of the painters. 
Phenicochrotte (or Melanochroite) is another lead chromate, contain- 
ing 23°0 of chromium trioxide, and having a dark red color; streak 
~ oP 
brick-red. Crystais usually tabular and reticulately arranged. G.=d°75. 
From Siberia. 
Vauquelinite. A lead and copper chromate, of a very dark green 
or pearly black color, occurring usually in minute irregularly aggre- 
gated crystals ; also reniform and massive. H.=2°5-3. G.=5°5-5'8. 
from Siberia and Brazil ; also at the lead mine near Sing Sing, in 
mammillary concretions. 
Stolzite, or lead tungstate. Insquare octahedrons or prisms. Color 
green, gray, brown, or red. Lustre resinous. H.=—2°‘5-8. G.=7-9- 
81. Contains 51 of tungstic acid and 49 of lead. 
Wulfenite, or lead molybdate. In dull-yellow octahedral crystals, 
and also massive. Lustre resinous. Contains molybdenum trioxide 
34°25, protoxide 64:42. From Bleiberg and elsewhere in Carinthia ; 
also Hungary. It has been found in small quantities in the Southamp- 
ton lead mine, Mass., and in fine crystals, at Phoenixville, Penn. 
Lead Sulphato-carbonates. There are two whitish or grayish ores 
of this composition called Lanarkite and Leadhillite. 'The former con- 
tains 71 per cent. of carbonate of lead ; the latter, 47. 
Pyromorphite.—Lead Phosphate. 
Hexagonal. In hexagonal prisms; often 
in crusts made of crystals. Also in globules 
or reniform, with a radiated structure. 
Color bright green to brown ; sometimes 
fine orange-vellow, owing to an intermix- 
ture with chromate of lead. Streak white 
or nearly so. Lustre more or less resinous. 
Nearly transparent to subtranslucent. Brit- 
ieee C= 6-5-7 “1. 
Composition.  Pb,O,P,+4PbCl,=Phos- 
phorus pentoxide 15°71, lead oxide 82:27, chlorine 2°62 
=100°60. B.B. fuses easily in the forceps, coloring the 
flame bluish green. On charcoal fuses, and on cooling, 
the globule becomes angular ; the coal is coated white from 
the chloride, and nearer the assay, yellow from lead oxide. 
Soluble in nitric acid. 
Diff. Has some resemblance to beryl and apatite ; but is 
quite different in its action before the blowpipe, and much 
higher in specific gravity. 

