Z IN
Z 1 N ( 498 )
Berg.
Klapr.
Pellet
84.
— 66. —
3 6 -
12.
~ 33- —
52.
O.
—- 0. —
12.
3-
-—■ 0. —
O.
1.
—' 0. —
0.
100.
99.
IOO.
It occurs in fecondary limeftone accompaniedby quartz, calcareous fpar, common calamine,&c.
Befides the localities above mentioned it alfooccurs.fin Derbyfhire.
Sp. 3. Blende. Black yack , of the Englifhminers. Pfeudogalena.
Of this there are the two following fubfpecies.
1 Subfp. Foliated B.
Its colour is wax and fulphur yellow, brownifhand olive green, reddifh or yellowifh, or blackifhbrown palling into perfect black, alfo hyacinthred, brownifh and blood red. It occurs in mafs,diffeminated or cryftallized. Its primitive formis the rhomboidal dodecahedron; the othersthat it prefents are.
1. The regular oftohedron.
2. Tire pyramidal tetrahedron.
3. Var 1, with all the edges truncated.
4. Ditto, with both the edges and folid anglestruncated.
5. A folid with twelve trapezoidal faces andtwelve ifofceles triangular faces.
6. The preceding variety with four of thefolid angles replaced by an equal number ofequilateral triangles.
The cryftals are generally fmall, and fo im-pacted together that it is not eafy to determinetheir forms: their furface is fmooth and fplen-dent. The external and internal luftre of thismineral is brightly fhining between relinous andadamantine, in the darker coloured varieties
Smith.
68.3 Oxyd of zinc,25. Silex,
4.4 Water,o. Oxyd of iron,o. Alumine.
97-7
pafling to femi-metallic. The fraflure is ftraitfoliated in fix directions, but when made acrofsthe laminae is imperfectly conchoidal. Its frag-ments are angular and pretty fharp-edged. Itprefents granular diftinCt concretions. Thelighter coloured cryftals are tranfparent andtranflucent, the darker coloured ones and themaffive varieties are tranflucent at the edges andopake. Its hardnefs is about equal to that offiuor fpar; it is brittle and eafily frangible.Sp. gr. 4.04 =4-id.
2 Subfp. Fibrous B.
Its colour is iron grey mixed with yellowifhparticles; it occurs in cellular, reniform, andftala£titical maffes : externally it is dull: inter-nally it is gliftening or glimmering ; its fra£turein one direction is finely and divergingly fibrous ;the crofs fracture is conchoidal; it it-compofedof curved lamellar diftindt concretions. It isopake, moderately hard and brittle. Sp. gr.3.63.
It has hitherto been found only at Geroldfeckin the Brifgau, in a vein accompanied by galenaand heavy fpar.
The yellow foliated blende is phofphorefcentby friction, even under water. Several of theblendes give out an hepatic odour by friction,and ftill more of them by digeftion in muriaticacid.
They have been fubjeCted to various analyfes,but hitherto not with fufficient precifion. Thefollowing is a table of the different refults.
Zinc 1
Sulphur
Iron
Lead
Copperl Arfenic
Fluoric
Water
Silex
Alumine
Yellow B. \
64.
20.
5-
O.
O.
O-
4-
6.
1.
O.=IQ 0 .
by Bergman JBrown B. \
44.
*7-
5-
0.
O.
O.
O.
5-
24.
5.=ioo.
by Bergman Jby Dr.Thomfon
58.8
23-5
8.4
0.
0.
O.
0.
O.
7-
o.= 97.7
Black B. "1
by Bergman J
45-
29.
9-
6.
O.
I.
0.
6.
4-
o.z^rioo.
by Lampadius
S3-
26.
12.
O.
O.
5-
0.
4-
O.
0.:=I00.
black li.with me-1/ tallic luftre >
52-
26.
8.
0.
4-
0.
0.
4-
6.
o.=ioo.
by Bergman JFibrous B. \
by Hecht J
62.
21.
3-
5 -
O.
I.
0.
4-
0.
2.= 98 -