Mineral.  Scorodite

Formula.                 [...Fe=][.....As] + 4[.H].

Behavior

  (1) in glass-bulb.  Evolves water.

  (2) in open tube.  Gives off water and AsO^{3}.

  (3) on charcoal.  Emits arsenical fume and in the reducing flame
                         fuses to a magnetic mass having a metallic
                         lustre.

  (4) in forceps.  I. As on charcoal.  Colors the outer flame
                         blue.

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

  (6) in mic. salt.  As in borax.

(7) with carb. soda.  As alone on charcoal.

(8) Special reactions.  Gives the arsenic reactions.

* * * * *

Mineral.  Cube ore

Formula.                 [.Fe]^{3}[.....As] +
[...Fe=]^{3}[.....As]^{2} + 18[.H].

Behavior

(1) in glass-bulb.  Evolves much water.

(2) in open tube.  As the preceding.

(3) on charcoal.  As the preceding.

(4) in forceps.  As the preceding.

(5) in borax.  As the preceding.

(6) in mic. salt.  As in borax.

(7) with carb. soda.  As the preceding.

(8) Special reactions.  As the preceding.

* * * * *

MANGANESE.

* * * * *

Mineral.  Manganblende

Formula.  MnS.

Behavior

(1) in glass-bulb. —­

  (2) in open tube.  Gives off SO^{2} and becomes greyish green on
                         surface.

  (3) on charcoal.  Is slowly roasted and converted into oxide.

  (4) in forceps.  V.

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

  (6) in mic. salt.  In the unroasted state, dissolves with much
                         ebullition and detonation due to elimination of
                         sulphide of phosphorus.  The bead then exhibits
                         the characteristic violet color of manganese.

  (7) with carb. soda.  Forms a slaggy mass, which laid on silver and
                         moistened, gives the sulphur reaction.

  (8) Special reactions. —­

* * * * *

Mineral.  Pyrolusite

Formula. [..Mn].

Behavior

  (1) in glass-bulb.  Frequently gives off a small quantity of water
                         and, when strongly heated, oxygen.

  (2) in open tube. —­

  (3) on charcoal. —­

  (4) in forceps.  V.