Rasendrapurana 26.8

Rasendrapurāṇa 26.8

paryāyaḥ pāṇḍurasyāpi nīlakaṇṭha iti śrutaḥ
uttamo nīlakaṇṭhaśca sphāṭikābhaśca madhyamaḥ
guḍābhaścādhamaḥ prokto rasaśāstraviśāradaiḥ