Nature may tint metals with a color that is foreign to them. The true color of copper is red yet sometimes it occurs yellow. The Greeks call this όρείχαλκος. Sometimes copper is white and this is called ψευδάργυρος. The latter has the appearance of silver, the former the appearance of gold. Pliny writes that the yellow copper has a characteristic and pleasing beauty by day. Strabo writes that the white copper was made in Teuthrania near Andera and in Lydia near Mt. Tmolus. Copper can be colored artificially to imitate nature.
Native cadmia 1 is added to copper to make brass (orichalcum). According to Pliny at one time Livian copper was used chiefly in making brass and later, Marian copper. Brass is made in the following way. Alternate layers of the best broken copper and cadmia are placed in a tall crucible. When it is full it is lowered into a furnace in a space that has been hollowed out and is fired as if it were in a covered passage. When entirely melted, the copper is changed into brass with the color of gold. This is the common method. By another method sheets of copper three-quarters of an inch wide are placed in a crucible similar to those used in casting silver but having the outside covered with a clay containing iron scale and the inside covered with the most highly refined honey. The thin sheets of copper are also coated with honey. They then sprinkle over the copper a . . .