Kautilya's Arthashastra 2.11.32

2.11.32

śuddhasphaṭiko mūlāṭavarṇaḥ śītavṛṣṭiḥ sūryakāntaś ca / iti maṇayaḥ //

That which is characterised with blue lines, that which is of the colour of the flower of Kaláya (a kind of phraseolus), or which is intensely blue, which possesses the colour of Jambu fruit (rose apple), or which is as blue as the clouds is the Indraníla gem; Nandaka (pleasing gem), Sravanmadhya (that which appears to pour water from its centre), Sítavrishti (that which appears to pour cold shower), and Súryakánta (sunstone) are other forms of gems.