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PDF(4) in forceps. —
(5) in borax. The oxide
formed upon charcoal gives the lead
reaction.
(6) in mic. salt. As in borax.
(7) with carb. soda. As alone on
charcoal. The fused alkali gives a
sulphur
reaction on silver.
(8) Special reactions. —
* * * * *
Mineral. Clausthalite
Formula. PbSe.
Behavior
(1) in glass-bulb. Decrepitates slightly.
(2) in open tube. Forms a sublimate
of selenium, which is grey
when
thickly deposited, and red when thin.
(3) on charcoal. Gives off
fumes smelling strongly of selenium
and
coloring the flame blue. In the reducing
flame
fuses partially and incrusts the charcoal
with
Se and PbO. After some time a black
infusible
mass alone remains.
(4) in forceps. —
(5) in borax. The infusible
residue obtained upon charcoal
gives
an iron and sometimes copper and cobalt
reaction.
(6) in mic. salt. As in borax.
(7) with carb. soda. With carbonate
of soda, oxalate of potash yields
a
metallic bead, the fused alkali laid upon
silver
and moistened produces a stain similar to
that
produced by sulfur.
(8) Special reactions. —
* * * * *
Mineral. Jamesonite
Formula. [,Pb]^{3}[,,,Sb]^{2}.
Behavior
(1) in glass-bulb. Fuses and
gives off some sulphur, sulphide of
antimony
and antimony which condense in the neck
of
the bulb.
(2) in open tube. Fuses and
emits dense white fumes of SbO^{3},
which
pass off and redden blue litmus paper.
(3) on charcoal. Fuses with
great ease evolving much SbO^{3} and
PbO,
which incrusts the charcoal around the
mineral.
When the fumes have ceased, a small
bead
of metallic lead remains.
(4) in forceps. —
(5) in borax. The yellow
incrustation formed upon charcoal
gives
the reaction of lead, and the white those
of
antimony.
(6) in mic. salt. As in borax.
(7) with carb. soda. As alone on
charcoal. The fused alkali gives the
sulphur
reaction on silver.
