कालायसस्यार्धभागाभ्यक्तं कृष्णं भवति ॥ कZ_०२.१३.५५ ॥
kālāyasasyārdhabhāgābhyaktaṃ kṛṣṇaṃ bhavati
काळ्या लोखंडाच्या (कालायस) अर्ध्या भागाने लेप/उपचार केल्यास ते काळे होते.
Surface treatments can disguise base metals; state knowledge of such methods supports enforcement against fraud in bullion, ornaments, and coin-like pieces.