ἔστιν θάλασσα, τίς δέ νιν κατασβέσει;
τρέφουσα πολλῆς πορφύρας ἰσάργυρον
κηκῖδα παγκαίνιστον, εἱμάτων βαφάς.
'There is the sea - who could ever dry it up? - which grows an ever-renewed ooze of abundant purple, worth it's weight in silver, to dye clothing with.'
πορφύρα means 'purple dye'. I wonder whether there's some sort of play with the word πορφύρεος, common at least in Homer, which refers to the agitated sea.