तापो बहिरन्तश्च समः किञ्जल्कवर्णः कुरण्डकपुष्पवर्णो वा श्रेष्ठः ॥ कZ_०२.१३.२६ ॥
tāpo bahirantaś ca samaḥ kiñjalkavarṇaḥ kuraṇḍakapuṣpavarṇo vā śreṣṭhaḥ
Gold is best when the heating/assay effect is uniform on the outside and inside, and when its colour is like pollen (golden-yellow) or like the kuraṇḍaka flower.
It creates an enforceable state standard for purity/quality so officials can accept, reject, price, and tax gold consistently and detect adulteration.
It targets fraud where only the surface is made to appear pure; the state requires internal purity verified through assay.