Su suggerimento di @Yoghi.
Un articolo di ZME Science mostra il fenomeno antartico degli iceberg striati, spiegando l’origine dei loro colori.
The different colours appear due to various reasons, but generally speaking they appear because some layers of ice form in special conditions. Blue stripes are the most common, and they appear when crevices are filled with water and they freeze so fast that no bubbles are formed. However, things are different with the other ones.