Minerals and Metals in Ancient India v2.c40.s1.2

v2.c40.s1.2

Utilisation of big-size rocks containing specific minerals involved size-reduction and purification and, in the case of metal extraction, certain steps in process metallurgy. Jambhaka (7.1.61) alluded to crushing using jaw which reminds us of the modern-day jaw crusher. Further size reduction or grinding peṣam could be done under dry condition (śuṣka/rūkṣa/cūrṇa) or under wet condition (udpeṣam) (Pāṇ., 3.4. 35-38, 6.3.58, etc.). Crushing resulted in small particles of different sizes and densities, and therefore these were separated (or purified) from each other by several technique including winnowing or paripavana (8.4.34). Winnowing is a pneumatic (air) separation/purification technique exemplified in the traditional separation between rice and husk. Pavana means air and pāvaka means purifier. There seems to be an etymological relationship between the two words.