Rasendracudamani 12.5

12.5

vṛttāyattaṃ samagātraṃ māṇikyaṃ śreṣṭhamucyate /
{nīlagandhi:: parīkṣā}
nīlaṃ gaṅgāmbusambhūtaṃ nīlagarbhāruṇacchavi /
pūrvamāṇikyavacchreṣṭhaṃ māṇikyaṃ nīlagandhi tat //

round-oblong, and uniform in body: such a ruby is declared superior.
That which is bluish, born of the water of the Gaṅgā, reddish with a bluish interior tint,
and superior like the previously mentioned ruby, is the *nīlagandhi* ruby.