* * * * *

Mineral. Zincblende

Formula. ZnS.

Behavior

(1) in glass-bulb. Decrepitates strongly.

(2) in open tube. Evolves SO and becomes white or yellow if
containing iron.

(3) on charcoal. V. In the reducing flame incrusts the charcoal
with ZnO; also with CdO, if that metal be
present.

(4) in forceps. --

(5) in borax. The roasted mineral gives a zinc reaction, and
sometimes a slight iron reaction.

(6) in mic. salt. As in borax.

(7) with carb. soda. As alone on charcoal. Moreover colors the flame
blue. The fused alkali gives a S reaction on
silver.

(8) Special reactions. --

* * * * *

Mineral. Red oxide of zinc

Formula. [.Zn].

Behavior

(1) in glass-bulb. --

(2) in open tube. --

(3) on charcoal. In the reducing flame forms a thin incrustation
of oxide of zinc on the charcoal.

(4) in forceps. V.

(5) in borax. Generally gives a manganese and slight iron
reaction in addition to that of zinc.

(6) in mic. salt. As in borax.

(7) with carb. soda. On charcoal, forms a thick incrustation of ZnO.

(8) Special reactions. With carbonate of soda and nitre on platinum
foil gives manganese reaction.

* * * * *

Mineral. Electric calamine

Formula. 2[.Zn]^{3}[...Si] + 3[.H]

Behavior

(1) in glass-bulb. Gives off water and becomes white and opaque.

(2) in open tube. --

(3) on charcoal. --

(4) in forceps. V.

(5) in borax. Dissolves to a clear glass, which cannot be
rendered opaque by the intermittent flame.

(6) in mic. salt. Dissolves to a clear glass, which becomes opaque
on cooling. Silica remains insoluble.

(7) with carb. soda. With carbonate of soda alone is infusible. With
2 parts of alkali and 1 of borax fuses to a
glass and sets free [.Zn], which incrusts the
charcoal.