Anandakanda 2.1.319

2.1.319

nānāvarṇaśca vijñeyaḥ kṛṣṇasteṣu guṇottaraḥ /
rālastu śiśiraḥ snigdhaḥ kaṣāyastiktako rase //

And variegated in color, it should be known; of these, the black is superior in virtues. / Rāla is cooling, unctuous, astringent and bitter in taste;