The Icebergs of Antarctica, sometimes display streaks, originated by layers of snow, that react accordingly to different conditions.
Blue streaks are created when a crack in the ice fills up with water, and does not freeze rapidly, and bubbles of air are trapped.
Sometimes, when a iceberg falls in the ocean, a veil of salty water freezes on its bottom. If that veil, happens to be rich with algae, it could display a green shade.
Brown, yellow, and black lines are formed by sediments, when the blade of ice ground the rocks, on its long way down towards the ocean.