th
Na_{2}CO_{3} and KCN, the ore is reduced to the metal.

~Cuprite~, Cu_{2}O, Cu . 89, O . 11.--

H = 3.5-4.0, G = 5.5-6.15.

Color, intense crimson-red. Before the Bp. on Ch. blackens and fuses
quietly, and finally yields a metallic globule of copper. Before the Bp.
on Ch. with Na_{2}CO_{3} and KCN it is easily reduced.

~Malachite~, 2 CuO + CO_{2} + H_{2}O, CuO . 72, CO_{2} . 20, H_{2}O . 8.--

H = 3.5-4.0, G = 3.90-4.03.

Color, bright green. Occurs generally in mammillated concretions.
Lustre, shining and fracture, silky. Heated in an ignition tube yields
water and blackens. Before the Bp. on Ch. it fuses to a metallic
globule. Before the Bp. on Ch. with Na_{2}CO_{3} and KCN it is easily
reduced. With borax bead gives characteristic coloration.

~Azurite~, 3 CuO + 2 CO_{2} + H_{2}O, CuO . 69, CO_{2} . 26, H_{2}O . 5.--

H = 3.5-4.0, G = 3.77-3.83.

Color, azure-blue. Occurs usually in crystallized or globular masses.
Lustre, earthy or vitreous. Before the Bp. and with other reagents
behaves like malachite.

~Chrysocolla~, CuO + SiO_{2} + 2 H_{2}O, SiO_{2} . 34.2, CuO . 45.3,
H_{2}O . 20.5.--H = 2.0-3.0, G = 2. Color, bluish-green, closely
resembling malachite. Occurs usually as an incrustation, its surface
being very smooth, like enamel. In an ignition tube it blackens and
yields water. Before the Bp. on Ch. in O. F. it blackens, coloring the
flame bright green; in the R. F. it turns red. Before the Bp. on Ch.
with Na_{2}CO_{3} yields metallic copper. In borax bead it reacts for
copper.

~Atacamite~, CuCl_{2} + 3 CuO_{2}H_{2}--Cl . 16.6, O . 20.3, Cu . 50.1,
H_{2}O . 13.0.--

H = 3.0-3.5, G = 3.75-3.77.

Color, green to blackish green. Lustre, adamantine to vitreous. In an
ignition tube yields water. Before the Bp. on Ch. colors flame blue.
Before the Bp. on Ch. with Na_{2}CO_{3} and KCN is reduced to the metal.
In borax bead it reacts for copper.

ORES OF IRON

~Limonite~, 2 Fe_{2}O_{3} + 3 H_{2}O, Fe_{2}O_{3} . 86, H_{2}O . 14.--H =
5.0-5.5, G = 3.6-4.0. Color, brown to ochre-yellow. Earthy or
semi-metallic in appearance. In an ignition tube yields water. Before
the Bp. on Ch. infusible. In borax bead reacts for iron.

~Hematite~, Fe_{2}O_{3}, Fe . 70, O . 30.--

H = 5.5-6.5, G = 4.9-5.3.

Color, dark steel-gray to iron-black. Lustre, metallic. When pulverized
yields a red powder. Before the Bp. on Ch. infusible. After long
roasting becomes magnetic. In bo