Rasarnava 6.133

6.133

vandhyācūrṇaṃ tu vaikrāntaṃ samāṃśena tu cūrṇayet
ajāmūtreṇa saṃbhāvya chāyāśuṣkaṃ tu kārayet
andhanāle dhamitvā tu mūṣāsattvaṃ tu jāyate //

One should grind vaikrānta with an equal part of powder of bitter loofah; / having macerated it with goat urine, one should dry it in the shade; / having blown it in a blind pipe, the metallic essence is produced in the crucible.