Blue Iceberg, Anarctica Royalty-Free Stock Image

Ice forms from compacted snow. As the crystal structure becomes less intricate the ice becomes more dense and the colour appears increasingly blue. The most dense ice is that found at the bottom of glaciers and may be thousands of years old. The maximum compression of ice is 90% that of water which is why it will always float and up to nine tenths of an iceberg is under the surface.