Digha Nikaya 1:612
SUJATOSeyyathāpi nāma umāpupphaṁ nīlaṁ nīlavaṇṇaṁ nīlanidassanaṁ nīlanibhāsaṁ. Seyyathā vā pana taṁ vatthaṁ bārāṇaseyyakaṁ ubhatobhāgavimaṭṭhaṁ nīlaṁ nīlavaṇṇaṁ nīlanidassanaṁ nīlanibhāsaṁ.
They’re like a flax flower that’s blue, with blue color and blue appearance. Or a cloth from Varanasi that’s smoothed on both sides, blue, with blue color and blue appearance.