times sulphide of arsenic. Also
HS.

(2) in open tube. Sulphurous acid and sometimes arsenious acid are
evolved.

(3) on charcoal. Gives off some sulphur, which burns with a blue
flame. Residue fuses to a magnetic bead.

(4) in forceps. --

(5) in borax. The roasted mineral gives a strong iron
reaction.

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

(7) with carb. soda. Fuses to a black mass, which spreads out on
charcoal and gives the sulphur reaction on
silver.

(8) Special reactions. --

* * * * *

Mineral. Magnetic pyrites

Formula.
[,Fe]^{5}[,,,Fe=].
Behavior

(1) in glass-bulb. --

(2) in open tube. Evolves sulphurous acid.

(3) on charcoal. Fuses to a magnetic bead black on the surface,
and with a yellow shining fracture.

(4) in forceps. --

(5) in borax. As iron pyrites.

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

(7) with carb. soda. As iron pyrites.

(8) Special reactions. --

* * * * *

Mineral. Mispickel

Formula. FeAs + FeS^{2}.

Behavior

(1) in glass-bulb. A red sublimate of AsS^{2} is first formed and
then a black sublimate of metallic arsenic.

(2) in open tube. Sulphurous and arsenious acids are evolved, the
latter forming a white sublimate.

(3) on charcoal. Gives off much arsenic forming a white
incrustation and fuses to a magnetic globule.

(4) in forceps. --

(5) in borax. As iron pyrites.

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

(7) with carb. soda. As iron pyrites.

(8) Special reactions. --

* * * * *

Mineral. Magnetic iron ore

Formula. Fe^{3}O^{4}

Behavior

(1) in glass-bulb. --

(2) in open tube. --

(3) on charcoal. --

(4) in forceps. In the blue flame, fuses on edges and remains
magnetic.

(5) in borax. Gives the iron reaction.

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

(7) with carb. soda. --

(8) S