Copper Borate
:
ON THE SECONDARY, GREEN.
is obtained by precipitating sulphate of copper with borax, washing the
residue with cold water, and, after drying, igniting it, fusion being
carefully avoided. In this manner, a pretty yellowish green is produced,
which upon longer ignition assumes a dark green shade: the mass is
levigated for use. The compound has the objection of being glassy, and
possessing little body, but is preferable to verdigris as to permanence.