References

BhPr, 1, 8, 25.1
  kṛṣṇaṃ rūkṣam atistabdhaṃ śvetaṃ cāpi ghanāsaham /Context
RSK, 2, 15.1
  mlecchastu kṣālitaḥ kṛṣṇo rūkṣaḥ stabdho ghanāsahaḥ /Context