[lsb]

There's a beautiful essay by the late William Harris about exactly this: http://wayback.archive-it.org/6670/20161201175416/http://com...

The ancient Greek word purphureos, which comes into English as purple, meant something like "dark and shimmering", and described wine and blood and the sea as purphureos. Much like we describe many things as "iridescent" that aren't rainbow-y (Gk iris = rainbow)