A. _Erinite_, rhomboidal arseniate of copper, micaceous copper,
_kupferglimmer_. Emerald green; specific gravity 4·043; scratches
calc-spar; yields water by heat; fusible at the blowpipe, and reducible
into a white metallic globule. Soluble in nitric acid; the solution
throws down copper by iron. It consists of arsenic acid 33·78; oxide of
copper 59·24; water 5; alumina 1·77. It is found in Cornwall, Ireland,
Hungary.
B. _Liroconite_; octahedral arseniate of copper; lens ore, so called
from the flatness of the crystal. Blue; specific gravity 2·88;
scratches calc-spar. It consists of arsenic acid 14; oxide of copper 49;
water 35. It is found in Huel-Mutrel, Huel-Gorland, Huel-Unity, mines in
Cornwall.
C. _Olivenite_; right prismatic arseniate of copper; olive-ore. Dull
green; specific gravity 4·28; scratches fluor; yields no water by heat;
fusible at the blowpipe into a glassy bead, enclosing a white metallic
grain. It consists of arsenic acid 45, oxide of copper 50·62. It affords
indications of phosphoric acid, which the analysts seem to have
overlooked. It occurs in the above and many other mines in Cornwall.
D. _Aphanese._ Trihedral arseniate of copper. Bluish green, becoming
gray upon the surface; specific gravity 4·28; scarcely scratches
calc-spar; yields water with heat; and traces of phosphoric acid.
The fibrous varieties called wood copper, contain water, and resemble
the last species in composition.