Matsya Purana 227.75

227.75

nāmajātigṛhaṃ teṣāmabhadroheṇa kurvataḥ.
nikṣepyo'yo mayaḥ saṅkurjvalannāsye daśāṅgulaḥ .. 227.74 ..

[A king should put a red, hot iron spike twelve Angulas long in the mouth of a Śûdra who vilifies violently one, taking his name, caste and house—74

A Brâhmaṇa who indulges with a Châṇḍâla woman or a woman of a different caste or eats their food or accepts a gift from them unknowingly tolas of gold or silver according to the seriousness of the offence The one who breaks anyone's bone should be exiled from the country—87