~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, G = 5.77-5.86. Color, black to dark cochineal-red. Lustre, metallic, adamantine. In an ignition tube it yields on continued heating a sublimate of antimony sulphide. Before the Bp. on Ch. it gives a coating of antimony trioxide. Before the Bp. on Ch. with Na_{2}CO_{3} is reduced to metallic silver. ~Proustite~, Ag_{3}S_{3}As, Ag . 65.5, As . 15.1, S . 19.4.--H = 2.0-2.5, G = 5.57-5.64. Color, light red. Lustre, splendent, adamantine. Before the Bp. on Ch. it behaves like pyrargyrite, save that it gives off arsenical fumes instead of antimonious oxide.