Page 241 - Copper and Bronze in Art: Corrosion, Colorants, Getty Museum Conservation, By David Scott

Copper Sulfides

CHAPTER g

Take a thin leaf of Nepalese copper and embed it in powdered sulphur.
The substances are to be placed inside a saucer-shaped earthenware
vessel and covered with another. The rims are luted with sugar or
powdered rice-paste. The apparatus is heated in a sand-bath for three
hours. The copper thus prepared is powdered and administered with
other drugs.—CHAKRAPANI DUTTA 1

τ

are
sulfides
he
copper
a
group
of com­
difficult
diverse
and
pounds with dubious stoichiometry and crystallinity. Many new members have been identified
in recent years. Sulfides are found in corrosion that varies from patinas formed in oxygen-
deficient, aqueous environments to tarnish caused by undesirable museum pollutants. As inlay,
copper sulfides were used to make the dense black substance, known as niello, that was used for
decorating the surface of metals as long ago as the Bronze Age.
One interesting use of sulfides was medicinal, as alluded to by Chakrapani Dutta in his
Chakradatta of 1050 (Ray 1956). Suspensions or ointments made from malachite, copper sulfides,
verdigris, or small hammered flakes of elemental copper were used to treat pain in the muscles,
spinal cord, or joints. In his Natural History, Pliny the Elder gives this prescription for a balm to
"soften the member of" the knee: