all quantities of Fe_{2}O_{3}, Al_{2}O_{3}, BaO, SiO_{2},
etc., associated with it.

H = 0.5-6.0, G = 3.0-4.2. Color, dull black. Heated in an ignition tube
yields water in abundance, otherwise it behaves like pyrolusite.

ORES OF MERCURY

~Native Mercury, Hg.~--G = 13.5-13.6. Color, silver-white. Is liquid at
all ordinary temperatures. Heated in an ignition tube is volatilized,
the vapors condensing in the upper end of tube to small metallic
globules of Hg. Before the Bp. on Ch. it is volatilized. Frequently
contains Ag.

~Cinnabar~, HgS_{2}, Hg . 86, S . 14.--

H = 2.0-2.5, G = 8.0-8.2.

Color, scarlet-red to brick-red. Lustre, non-metallic. When pulverized
yields a powder of vermilion-red color. Heated in an ignition tube it
volatilizes, yielding a black sublimate, which by friction becomes red.
Before the Bp. on Ch. it is wholly volatilized. Heated in an ignition
tube with Na_{2}CO_{3} metallic mercury sublimes, condensing in the
upper portion of the tube in minute globules.

ORES OF NICKEL

~Millerite~, NiS, Ni . 64.4, S . 35.6.--

H = 3.0-3.5, G = 5.2-5.6.

Color, brass-yellow. Brittle. Before the Bp. on Ch. it fuses to a
magnetic, metallic globule. The roasted mineral gives in the borax bead
the color reaction characteristic of nickel, and sometimes that of
cobalt, which is often associated with it.

~Niccolite~, NiAs, Ni . 44, As . 56.--

H = 5.0-5.5, G = 7.35-7.67.

Color, pale copper-red. Lustre, metallic. Very brittle. Heated in an
ignition tube yields a copious sublimate of arsenious oxide, the residue
falling to a greenish powder. Before the Bp. on Ch. fuses to a white
brittle globule emitting arsenical fumes. In borax bead gives color
characteristic of nickel. Frequently in this mineral a portion of the
arsenic is replaced by antimony.

ORES OF SILVER

~Native Silver, Ag.~--

H = 2.5-3.0, G = 10.1-11.0.

Color, silver-white. Lustre, metallic. Ductile and malleable. Usually
occurs associated with Au, As, Sb, Cu, Fe, etc. Before the Bp. on Ch.
easily fuses to a globule which is surrounded with a dark red coating on
the coal.

~Argentite~, Ag_{2}S, Ag . 87.1, S . 12.9.--

H = 2.0-2.5, G = 7.20-7.36.

Color, blackish lead-gray. Lustre, metallic. Very sectile. Before the
Bp. on Ch. in O. F. intumesces with evolution of sulphur dioxide,
finally yielding a metallic globule of Ag.

~Pyrargyrite~, Ag_{3}SbS_{3}, Ag . 59.8, Sb . 22.5, S . 17.7.--H = 2.5,