Anandakanda 2.1.213

2.1.213

salile'pyavalīnaṃ ca tatsiddhaṃ hi śilājatu /
gomūtragandhi kṛṣṇaṃ guggulukābhaṃ saśarkaraṃ mṛtsnam /
snigdhamanamlakaṣāyaṃ mṛdu guru ca śilājatu śreṣṭham //

and dissolves in water: that indeed is genuine bitumen. / Smelling like cow's urine, black, resembling bdellium, grainy, fine, / unctuous, non-sour, astringent, soft, and heavy bitumen is the best;