Cakradatta (Cikitsasangraha) 65.90

65.90

14athavā vaktavyavidhiḥ
saṃskṛtakṛṣṇābhrakacūrṇamādāya .
lauhacaturthāṃśasama-
dvitricatuḥpañcaguṇabhāgam .. 90 ..

Or else, according to the prescribed rule, one may take powder of processed black mica, / in an amount equal to a fourth part of the iron, or two, three, four, or five times that part; 90