Minerals and Metals in Ancient India v1.c28.s9.3

v1.c28.s9.3

High lead-content copper alloy, known in Europe as ‘Caldarium’, is brittle and suitable only for castings; this has been used in Gujarat icons and some South Indian icons (vide Nos. 11-21 in Table 20.10). Item No. 12 contains nearly one-third by weight of the lead metal and 60 per cent copper; such copper-lead alloys have been defined as Śulvanāga in the Rasaratnasamuccaya (RRS, 8.18-19). The RRS has also defined two grades of brass: the malleable ritikā and the kākatuṇḍi. The latter when dipped in acidic sour gruel turns black; evidently this is leaded brass, the acid liberating the black globules and the elongated grains of lead which are insoluble in the copper-zinc alloy or brass phase.